Question 1

A velocity is given as $$(v_x = -3\ \mathrm{m/s},\ v_y = -4\ \mathrm{m/s}). $$What is the angle of the velocity vector as measured from the $$+x$$ axis?

Accepted Answer

233°

Question 2

The position of a particle as a function of time is given by $$x(t) = k_1$ - \frac{k_2$}{t^2$}. $$What is the acceleration of the particle as a function of time?

Accepted Answer

$$a(t) = -6\frac{k_2$}{t^4$}$$

Question 3

A 10 kg box slides horizontally without friction at a speed of 1 m/s. A constant force is applied in the direction of motion for 5 m, after which the box's speed is 2 m/s. What is the magnitude of the applied force?

Accepted Answer

3 N

Question 4

You try to push a 10-kg box across the floor. If the coefficient of static friction between the box and the floor is 0.20, what is the minimum force that must be applied to start the box moving from rest?

Accepted Answer

20 N

Question 5

Two objects are thrown from the top of a tall building with the same initial speed, one up and one down. Neglecting air resistance, how do their speeds compare when they hit the street?

Accepted Answer

They are traveling at the same speed.

Question 6

A fish with a weight of 14 N is weighed using two spring scales, each of negligible weight, as shown in the figure. What will be the readings of the scales?

Accepted Answer

Each scale will read 14 N.

Question 7

At a turning point of the trajectory of an object, which of the following is true?

Accepted Answer

Only the instantaneous velocity in that direction must be zero.

Question 8

Refer to the first image (two blocks, 1 kg and 3 kg, with 5 N and 3 N forces). Considering only the horizontal forces, what is the net force on the larger block?

Accepted Answer

Between 2 N and 3 N.

Question 9

A load is lifted vertically by a crane with a constant acceleration $$a_1 = 0.20$$\ \mathrm{$$m/s^2$$}$$ for $$\Delta $$t_1 = 5.0$$\ \mathrm{s}$$, then moves at constant velocity for $$\Delta $$t_2 = 10.0$$\ \mathrm{s}$$, and finally slows down with a_3$ = 0.25\ \mathrm{m/s^2$}$$ until it stops. What is the expression for the constant velocity $$v$$ during $$\Delta t_2$?

Accepted Answer

$$v = a_1$ \Delta t_1$

Question 10

In the system shown in the third image (three boxes, one on a ramp at angle $$	heta$$), if the ramp is frictionless and the applied force is 420 N, which box will have the greatest acceleration?

Accepted Answer

All boxes have the same acceleration.

Question 11

A car is parked on a hill. Which of the following best describes the forces acting on the car?

Accepted Answer

The weight acts downward, the normal force acts perpendicular to the surface, and friction acts up the incline.

Question 12

A 10 kg box is at rest on a horizontal surface. If the coefficient of kinetic friction is $$\mu_k = 0.15$$, what is the force of friction when the box is sliding?

Accepted Answer

$$F_f = 14.7\ \mathrm{N}$$

Question 13

A block slides down a frictionless incline of angle $$	heta = 30^\circ. $$What is the acceleration of the block?

Accepted Answer

$$a = g \sin 	heta$$

Question 14

A 2 kg object is moving at 3 m/s. What is its kinetic energy?

Accepted Answer

$$KE = 9\ \mathrm{J}$$

Question 15

A force $$F is $$applied to a mass $$m on a $$frictionless surface. If the force is doubled, what happens to the acceleration?

Accepted Answer

The acceleration doubles.

Question 16

A ball is thrown straight up with an initial velocity $$v_0. $$What is the velocity of the ball when it returns to the thrower's hand (neglecting air resistance)?

Accepted Answer

$$-v_0$

Question 17

A 5 kg object is acted on by a net force of 20 N. What is its acceleration?

Accepted Answer

$$4\ \mathrm{m/s^2$}$$

Question 18

A car accelerates from rest at a constant rate $$a$$ for time $$t. $$What is the distance traveled?

Accepted Answer

$$d = \frac{1}{2} a t^2$

Physics Exam Study Guidance: Forces, Motion, and Acceleration

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