Q: A 5 kg box is at rest on a horizontal surface. The coefficient of static friction between the box and the surface is $$\mu_s = 0.4. $$What is the maximum force that can be applied horizontally before the box starts to move?

$$F_{\text{max}} = \mu_s m g = 0.4 \times 5 \times 9.8 = 19.6\ \mathrm{N}$$

Q: A student drops a ball from a height of 20 m. Ignoring air resistance, how long does it take to reach the ground?

$$t = \sqrt{\frac{2h}{g}} = \sqrt{\frac{2 \times 20}{9.8}} \approx 2.02\ \mathrm{s}$$

Q: A 3 kg object moving at $$4\ \mathrm{m/s}$$ collides inelastically with a 2 kg object at rest. What is their final velocity?

$$v_f = \frac{m_1$ v_1$}{m_1$ + m_2$} = \frac{3 \times 4}{3 + 2} = 2.4\ \mathrm{m/s}$$

Question 1

A car travels 60 km east, then 80 km north. What is the magnitude of its displacement from the starting point?

Accepted Answer

$$\sqrt{60^2$ + 80^2$} = 100\ \mathrm{km}$$

Question 2

Which of the following quantities is a scalar?

Accepted Answer

Distance

Question 3

A ball is thrown straight up with an initial velocity of $$v_0. $$Neglecting air resistance, what is its velocity at the highest point?

Accepted Answer

$$0$$

Question 4

A 5 kg box is at rest on a horizontal surface. The coefficient of static friction between the box and the surface is $$\mu_s = 0.4. $$What is the maximum force that can be applied horizontally before the box starts to move?

Accepted Answer

$$F_{	ext{max}} = \mu_s m g = 0.4 	imes 5 	imes 9.8 = 19.6\ \mathrm{N}$$

Question 5

A student drops a ball from a height of 20 m. Ignoring air resistance, how long does it take to reach the ground?

Accepted Answer

$$t = \sqrt{\frac{2h}{g}} = \sqrt{\frac{2 	imes 20}{9.8}} \approx 2.02\ \mathrm{s}$$

Question 6

A 2 kg object moving at $$3\ \mathrm{m/s}$$ collides elastically with a stationary 1 kg object. What is the velocity of the 2 kg object after the collision?

Accepted Answer

$$v_{1f} = \frac{m_1$ - m_2$}{m_1$ + m_2$} v_{1i} = \frac{2 - 1}{2 + 1} 	imes 3 = 1\ \mathrm{m/s}$$

Question 7

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

Accepted Answer

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

Question 8

Which of the following best describes Newton's Third Law?

Accepted Answer

For every action, there is an equal and opposite reaction.

Question 9

A rotating disk has an angular velocity $$\omega$$ and a moment of inertia $$I. $$What is its rotational kinetic energy?

Accepted Answer

$$K = \frac{1}{2} I \$$omega^2$$

Question 10

A satellite orbits Earth in a circular path. Which force provides the centripetal acceleration?

Accepted Answer

Gravitational force

Question 11

A spring with spring constant $$k is $$compressed by a distance $$x. $$What is the potential energy stored in the spring?

Accepted Answer

$$U = \frac{1}{2} k x^2$

Question 12

A pendulum exhibits simple harmonic motion. Which statement is true at its maximum displacement?

Accepted Answer

Its velocity is zero and its acceleration is maximum.

Question 13

A fluid exerts pressure on the walls of its container. What is the formula for pressure at a depth $$h in a $$fluid of density $$\rho$$?

Accepted Answer

$$P = \rho g h$$

Question 14

A force $$F is $$applied at a distance $$r$$ from the axis of rotation. What is the torque produced?

Accepted Answer

$$	au = r F$$

Question 15

A 3 kg object moving at $$4\ \mathrm{m/s}$$ collides inelastically with a 2 kg object at rest. What is their final velocity?

Accepted Answer

$$v_f = \frac{m_1$ v_1$}{m_1$ + m_2$} = \frac{3 	imes 4}{3 + 2} = 2.4\ \mathrm{m/s}$$

Question 16

Which of the following is true about the center of mass of a system?

Accepted Answer

It moves as if all the mass and external forces act at that point.

Question 17

A student pushes a box across a rough floor at constant speed. Which statement is true about the forces acting on the box?

Accepted Answer

The applied force equals the frictional force.

Question 18

A rotating wheel speeds up from rest to an angular velocity $$\omega in $$time $$t$$ under constant angular acceleration $$\alpha. $$What is $$\alpha$$?

Accepted Answer

$$\alpha = \frac{\omega}{t}$$

Question 19

A block of mass $$m is $$attached to a spring and oscillates with period $$T. $$What is the relationship between $$T$$, $$m$$, and the spring constant $$k$$?

Accepted Answer

$$T = 2\pi \sqrt{\frac{m}{k}}$$

AP Physics 1: Algebra-Based – Course and Exam Description (Effective Fall 2024)

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