Question 1

A ball is thrown vertically upward with an initial velocity $$v_0. $$Neglecting air resistance, which equation gives the position $$y(t) of $$the ball at time $$t$$? Assume upward is positive and $$g is $$the acceleration due to gravity.

Accepted Answer

$$y(t) = v_0$ t - \frac{1}{2} g t^2$

Question 2

A 10 kg box is pushed across a horizontal frictionless surface with a constant force of 50 N at an angle of $$35^\circ$$ above the horizontal. What is the normal force exerted by the floor on the box?

Accepted Answer

$$F_N = mg - 50 \sin 35^\circ$$

Question 3

Which of the following best describes the net force acting on an object moving in uniform circular motion?

Accepted Answer

A centripetal force always points towards the center of the circle.

Question 4

Two blocks of masses 4.0 kg and 8.0 kg slide down a frictionless plane inclined at $$36^\circ$$ from the horizontal. They are released from rest at the same height and at the same time. Which statement is correct?

Accepted Answer

Both blocks reach the bottom simultaneously.

Question 5

A frictionless roller coaster car of mass 888 kg tops the first hill A with speed $$v_A = 12.0 m/s at a $$height $$h_A = 20 m. $$What is the speed of the car at point B at ground level?

Accepted Answer

$$v_B = \sqrt{v_A^2$ + 2gh_A}$$

Question 6

The Apollo 10 orbits the moon in a circular orbit of radius $$1.85 	imes 10^6$ m, taking 119 minutes to go around once. What is the mass of the moon in kg? (Use G = 6.67$$ 	imes $$10^{-11} N m$^2/kg$^2)$$

Accepted Answer

$$M = \frac{4\pi^2$ r^3$}{G T^2$}$$

Question 7

A 15.0 kg library book falls 1.5 m vertically from a shelf and lands 3.7 m horizontally from the shelf edge. How much work is done by gravity on the book during its fall?

Accepted Answer

$$W = mgh$$

Question 8

A 10 kg box is pushed on ice and released at a speed of 1.5 m/s. When the box has traveled 24 m, its speed is reduced to 0.5 m/s. What is the coefficient of kinetic friction $$\mu_k$$ between the box and the ice?

Accepted Answer

$$\mu_k = \frac{v_0$^2 - v^2$}{2gd}$$

Question 9

Which equation expresses the conservation of mechanical energy for a system with no friction?

Accepted Answer

$$KE_i + PE_i = KE_f + PE_f$$

Question 10

A force $$\vec{F}$$ acts on a particle, causing a displacement $$\vec{d}. $$Which equation gives the work done by the force?

Accepted Answer

$$W = \vec{F} \cdot \vec{d}$$

Question 11

A ball moves with a constant acceleration $$a = 0.141 m/s$^2. $$Which statement is true about its velocity?

Accepted Answer

The component of the velocity must increase in time.

Question 12

Three connected blocks are pulled to the right on a horizontal frictionless table by a force $$T_3. $$What is the tension in the string between the first and second block ($$T_1$$)?

Accepted Answer

$$T_1$$ = $$T_3$$ - $$T_2$$

Question 13

Which of the following is the correct expression for the period $$T of a $$circular orbit of radius $$r$$ around a mass $$M$$?

Accepted Answer

$$T = 2\pi \sqrt{\frac{r^3$}{GM}}$$

Question 14

A car of mass $$m$$ moves at speed $$v in a $$circle of radius $$r. $$What is the magnitude of the centripetal force required?

Accepted Answer

$$F_c = \frac{mv^2$}{r}$$

Question 15

Which of the following is the correct formula for kinetic energy?

Accepted Answer

$$KE = \frac{1}{2}mv^2$

Question 16

A block slides down a frictionless incline of height $$h. $$What is its speed at the bottom?

Accepted Answer

$$v = \sqrt{2gh}$$

Question 17

Which equation gives the gravitational potential energy of an object of mass $$m at $$height $$h$$ above the ground?

Accepted Answer

$$PE = mgh$$

Question 18

A block of mass $$m is $$pulled across a frictionless surface by a force $$F at an $$angle $$	heta$$ above the horizontal. What is the horizontal component of the force?

Accepted Answer

$$F_x = F \cos 	heta$$

Physics Practice Exam 2: Study Notes on Kinematics, Forces, Work, Energy, and Circular Motion

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