A man pushes a cart with a force of 50 N at an angle of 50° to the horizontal. If the cart moves 45 m, how much work does he do on the cart? Round your answer to the nearest hundredth.
Answer: 1446.27J
Two balls with the same mass are rolled down two ramps, H1 and H2. What is the ratio, H2/H1, of their velocities at the bottom of the ramps?
Answer: 1.41.
What is the ratio of their respective work done on them?
Answer: 2.
$$P=\frac{W}{t}$$
If H2's ball takes twice as long to reach the bottom, what is the ratio of their respective power?
Answer: 1.
Suppose the block above has a mass of 10 kg. What is the net acceleration of the object?
Answer: 0.6 m/s².
The planet on the left has a mass of \(6.0 \times 10^{24}\) kg and the planet on the right has a mass of \(3.0 \times 10^{24}\) kg. The distance between their centers is \(3 \times 10^{12}\) m. What is the gravitational force between them?
Round G to \(7 \times 10^{-11}\) N m²/kg².
Answer: 1.4*1014 N.
If the distance between them is halved, what is the new gravitational force?
Answer: 5.6*1014 N.
A ball is thrown straight up with an initial velocity of 20 m/s. The gravitational acceleration is 10 m/s². What is its velocity after 2 seconds?
Answer: 0 m/s.
What is its velocity after 4 seconds?
Answer: -20 m/s.
How much time does it take to reach its maximum height?
Answer: 2 seconds.
How much time does it take to return to its original height?
Answer: 4 seconds.
$$x = V_0 t + \frac{1}{2} a t^2$$
How high does the ball go?
Answer: 20 m.
Assume the ball travels 2 meters horizontally at a constant rate while in the air. What is its horizontal velocity?
Answer: 0.5 m/s.
$$v^2 = V_0^2 + 2a(D.$$
After returning to its original height mid-air, the ball keeps falling and lands 80 meters below its starting height. What is its speed just before it hits the ground?
Answer: 44.72 m/s.
A woman reaches for a box coming off a semi-circular conveyer belt with pieces of velcro holding the box in place.If the belt is moving 3 m/s and is pulling box at 3 m/s² towards the center, what is the radius of the circular ramp?
Answer: 3 m
$$F_c = \frac{mv^2}{r}$$ Find the centripetal force acting on the 2 kg box at the ramp's peak height.
Answer: 6 N.
A force is applied to a wheel on a wall at an angle tangential to the radius. If the radius of the wheel is 0.5 m and the force applied is 20 N, what is the torque applied to the wheel?
Answer: 10 N·m.
How many degrees would the force have to rotate so the resulting torque was half of the original value?
Answer: 30 degrees.
A block is floating on a cylindrical water surface.The surface has an area of 10 m². The block has an area of 0.5 m² and a height of 0.1 m. If the block has a mass of 10 kg, what is the pressure it exerts on the surface?
Answer: 200 Pa.
$$P=pgh$$
The block sinks 1 meter and eventually reaches the bottom. What is the pressure the water exerts on the block?
Answer: 10000 Pa.
$$F_b=\rho Vg$$
When halfway down the tank, what is the buoyant force acting on it?
Answer: 500 N.
What is the buoyant force acting on the block if it is halfway submerged?
Answer: 250 N.
A fluid flows through a pipe with varying diameters. The cross-sectional area at pipe 1 is 0.5 m² and at point 2 is 0.1 m². If the velocity at pipe 1 is 5 m/s, what is the velocity at pipe 2?
Answer: 25 m/s.
$$P + \frac{1}{2}\rho v^2 = \text{constant}$$
Assume a fluid with the density of water moves through the pipes. If the pressure of pipe 1 is 400 kPa, Find the ratio, point 1/point 2, of the pressures at the two points. Express your answer as an integer.
Answer: 4.
A hot iron is plugged in right before it is used. It gains 100 J of heat from the cord and transfers 50 J of heat to the clothes. What is the change in internal energy of the iron?
Answer: 50 J.
A 100 g ice cube with a specific heat capacity of 2000 J/(kg·°c. is placed in a 1000 W microwave.If the ice cube has an initial temperature of -10 °C, how long does it take before the ice cube starts melting?
Answer: 2 seconds.
A canoe is hit by 5 small waves in 10 seconds. The wave travels past a point on the boat over the span of 2 meters from trough to trough. What is the wave speed?
Answer: 1 m/s.
$$f = \frac{1}{T}$$
What is the period of the wave from trough to crest, assuming symmetrical shape?
Answer: 1 s.
A sunburn causes skin to absorb \(7*10^{-19} J\) of energy from a photon. What is the frequency of the photon? Use \(7*10^{-34} J·s\) for Planck's constant. 1*1015 Hz.
$$E = \frac{hc}{\lambda}$$
What is the wavelength of the photon? Use \(3*10^{8} m/s\) for the speed of light.
Answer: 3*10-7 m.
A light ray in air enters a liquid, which has an index of refraction of 1.5. If the light ray hits the water surface at an angle of incidence of 30°, what is the angle of refraction?
Answer: 19.47°.
A converging lens has a focal length of 0.5m. If a person is standing 1 m away from the lens, twice as far as the focal point, what is the image distance to the right of the lens?
Answer: 1 m.
What is the person's image height? Type your answer
Answer: 1 m.
Is the image upright or inverted? Type your answer
Answer: inverted.
To make the image appear behind the person, would the person need to move to the right or left of the focal point? Type your answer
Answer: right.
The mirror bends, causing it to concave and diverge.If the person is still stand at twice the focal point, 1m to the left of the mirror, what is the distance of the image now?
Answer: 1/3 m.
$$V = IR$$
A circuit has a 12 V battery and a 4 Ω resistor. What is the current flowing through the circuit?
Answer: 3 A.
$$P = IV$$ $$P = \frac{V^2}{R}$$
What is the power consumed by the circuit?
Answer: 36 W.
$$P = I^2R$$
The circuit's resistance is doubled to 8 Ω. What is the new power consumed by the circuit?
Answer: 18 W.
Two point charges, \(q_1 = 2 \mu C\) and \(q_2 = -3 \mu C\), are both located 1 m from a point. One charge is parallel to the horizontal, while one is perpendicular. What is the net force between the charges?
Answer: 0.05 N.
$$E = \frac{kq}{r^2}$$ Supposed an object is isolated at a distance of 0.5m from the q1 charge.What is the electric field where the object is?
Answer: 72,000 N/C.
$$F = qE$$
If another charge with half the charge of q1 is placed at the same distance, what is the force acting on it?
Answer: 0.08 N.
$$F = qvB\sin\theta$$
If the force on the charge is 0.000001 N as the charge moves in a circular path at a velocity of 4 m/s 30° to the magnetic field, what is the magnetic field strength on the charge?
Answer: 0.5 T.
A wire carries a current of 2 A and is located 0.1 m from a point. What is the magnetic field strength at that point? Use \(4\pi \times 10^{-7}\) T·m/A for the permeability of free space.
Answer: 0.000004 T.
Which of the following would increase the magnetic field strength at that point?
a. Increasing the current in the wire
b. Decreasing the distance from the point to the wire
c. Both A and B
d. Neither A nor B
Answer: C.
A solution contains 0.36 liter of water (18 g/mol). How many moles of water are in the solution?
Answer: 20 mol.
$$M = \frac{n}{V}$$
The total solution has a volume of 0.5 L. What is the molarity of the water?
Answer: 40 M.
There are approximately 0.5 M of HCl in an initial aq solution. What is the final concentration of HCl if 0.1 L of solution is added to 0.1 L volume of water twice?
Answer: 0.17 M.
$$PV = nRT$$
A gas has a volume of 2 L at regular atmospheric pressure and a temperature of 300 K. How many moles of gas are in the container? Use 0.08 for R.
Answer: 0.08 mol.
If the volume doubled, which property would be halved, assuming everything else remains constant?
Answer: pressure.
Assuming this property is halved, the temperature would
Answer: remain constant.
a. Remain constant
b. Be doubled
c. Be halved
$$P_i = X_i \cdot P_{total}$$
Carbon dioxide exists in the blood near the alveoli at a partial pressure of 40 mmHg. The total pressure of dissolved gases in blood is roughly the same as the atmospheric pressure.If the total atmospheric pressure is 760 mmHg, what is the mole fraction of carbon dioxide in the blood? Answer: 0.05.
What would the mole fraction of oxygen entering the blood need to be if oxygen's partial pressure in the alveoli is 104 mmHg?
Answer: 0.14.
Answer: 128 g/mol.
$$pOH = -\log[OH^-]$$
$$pH + pOH = 14$$
A solution with 0.05 M of HCl is mixed with an equal volume and strength of a base of an unknown concentration.
If the resulting solution has a pH of 14, what would the concentration of the base be? 2.05 M.
Answer: 0.002 M
$$K_b = \frac{[OH^-][BH^+]}{[B]}$$
$$Kw= Ka \times Kb$$ What the resulting base dissociation constant?
Answer: 2.5*10-10.
$$pH = pK_a + \log\left(\frac{[A^-]}{[HA]}\right)$$
What is the pH of the solution? Round to the nearest tenth.
Answer: 2.7.
Which of the compounds will be included in the equilibrium constant expression?
Answer: Gases.
a. Gases
b. Solids
c. Liquids
d. All of the above
If glucose exists at a concentration of 0.1 M, oxygen 0.2 M, carbon dioxide 0.2 M, and water 0.4 M, what is the equilibrium constant for the reaction?
Answer: 1.
$$Q = \frac{[C]^c[D]^d}{[A]^a[B]^b}$$
Suppose the concentration of the reactants is halved and the concentration of the products is doubled. What is the reaction quotient?
Answer: 4096.
Which of the following statements is true? Type the letter of the correct answer.
Answer: B
a. The reaction will shift to the right to reach equilibrium
b. The reaction will shift to the left to reach equilibrium
c. The reaction will not shift
The standard free energy for the reaction above is typically -2870 kj/mol assuming normal conditions. Given the reaction quotient above, what is the change in Gibbs free energy?
Answer: -2868 kJ/mol.
$$G = \Delta H - T\Delta S$$
H in this equation represents change in enthalpy, or total heat in the system.
S in this equation represents change in entropy, or disorder in the system.
A reaction is exothermic and has a magnitude of enthalpy change 100 kJ/mol and an entropy of -0.2 kJ/(mol·K). What is the Gibbs free energy of the reaction at 300 K? -40 kJ/mol.
Which transition between phases is this most likely to represent? Type the letter of the correct answer.
Answer:
A ) Condensation
B ) Freezing
C ) Vaporization
D ) Melting
E ) Sublimation
F ) None of the above
$$\Delta G° = -RT\ln K_{eq}$$
Suppose the free energy in the above reaction is equal to the standard free energy. What is the equilibrium constant? Use 8.314 $$J/(mol·K) for R.
Answer: 9.3*106.
The rate of a reaction is as follows:
$$Rate = 0.1[H+]^2[OH-]$$
What is the order of the reaction?
Answer: 3.
If \(a\) is halved, what is the new order of the reaction?
Answer: 2.
Find the rate of the initial reaction if the concentration of H+ and OH- are both 0.1M. Enter the exact answer.
Answer: 0.0001 \(M^{−2}s^{−1}\).
$$k = Ae^{-\frac{E_a}{RT}}$$ Assuming the frequency factor is 1000 and the rate constant remains the same, what is the activation energy at 300 K? Use 8.314 \(J/(mol·K)\) for R.
Answer: 40.18 kJ/mol.
$$\ln\left(\frac{k_2}{k_1}\right) = \frac{E_a}{R}\left(\frac{1}{T_1} - \frac{1}{T_2}\right)$$
If the temperature halves by the time the products are formed, what is the rate constant of the products?
Answer: 1.8*10-8 \(M^{−2}s^{−1}\).
$$G = -nFE$$
A cell has a half-reaction of
\(Zn(s)→Zn^{2+}(aq)+2e−\) at the anode and
\(Cu^{2+}(aq)+2e−→Cu(s)\) at the cathode.If the cell has a standard cell potential of 1.1 V, what is the change in Gibbs free energy? Use 96485 C/mol for Faraday's constant. Round to the nearest whole number.
Answer: -212 kJ/mol.
Is the reaction spontaneous? Type yes or no.
Answer: Yes.
What kind of cell is this? Type the letter of the correct answer.
Answer: B
a. Electrolytic
b. Galvanic
The standard reduction potential is negative at the anode and positive at the cathode.
How many moles of electrons are transferred in the reaction?
Answer: 2 moles.
$$Q_{elec} = nF$$
What is the electric charge transferred in the reaction?
Answer: 192970 C.