Question 1

A ball is thrown straight up with an initial velocity of $$15\ \mathrm{m/s}. $$Neglecting air resistance, what is the maximum height the ball reaches above its starting point? (Use $$g = 9.8\ \mathrm{m/s^2$}.)$$

Accepted Answer

$$11.5\ \mathrm{m}$$

Question 2

A car accelerates uniformly from rest to $$20\ \mathrm{m/s} in$$ $$5\ \mathrm{s}. $$What is the magnitude of its acceleration?

Accepted Answer

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

Question 3

A projectile is launched at an angle of $$30^\circ$$ above the horizontal with an initial speed of $$40\ \mathrm{m/s}. $$What is the horizontal range of the projectile? (Neglect air resistance and use $$g = 9.8\ \mathrm{m/s^2$}.)$$

Accepted Answer

Question 4

A $$5\ \mathrm{kg}$$ block is pulled across a horizontal surface with a constant force of $$20\ \mathrm{N}$$, and the coefficient of kinetic friction is $$0.2. $$What is the acceleration of the block? (Use $$g = 9.8\ \mathrm{m/s^2$}.)$$

Accepted Answer

$$2.08\ \mathrm{m/s^2$}$$

Question 5

A $$2\ \mathrm{kg}$$ object is attached to a spring with a spring constant $$k = 100\ \mathrm{N/m}. $$The object is pulled $$0.1\ \mathrm{m}$$ from equilibrium and released from rest. What is the maximum speed of the object?

Accepted Answer

$$0.707\ \mathrm{m/s}$$

Question 6

A $$0.15\ \mathrm{kg}$$ baseball moving at $$40\ \mathrm{m/s} is $$hit straight back at $$60\ \mathrm{m/s} by a $$bat. What is the magnitude of the impulse delivered to the ball?

Accepted Answer

$$15\ \mathrm{kg\cdot m/s}$$

Question 7

A $$10\ \mathrm{kg}$$ box is at rest on a frictionless incline that makes a $$30^\circ$$ angle with the horizontal. What is the magnitude of the force parallel to the incline required to keep the box at rest?

Accepted Answer

$$49\ \mathrm{N}$$

Question 8

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

Accepted Answer

$$1\ \mathrm{m/s}$$

Question 9

A disk of mass $$2\ \mathrm{kg}$$ and radius $$0.5\ \mathrm{m}$$ rotates about its center with an angular velocity of $$10\ \mathrm{rad/s}. $$What is its rotational kinetic energy?

Accepted Answer

$$12.5\ \mathrm{J}$$

Question 10

A $$1\ \mathrm{kg}$$ mass is attached to a string and swung in a horizontal circle of radius $$2\ \mathrm{m} at a $$constant speed of $$4\ \mathrm{m/s}. $$What is the tension in the string?

Accepted Answer

$$8\ \mathrm{N}$$

Question 11

A satellite orbits Earth at a distance $$2$$ times the Earth's radius from the center of the Earth. What is the acceleration due to gravity at this altitude? (Assume $$g_0 = 9.8$$\ \mathrm{$$m/s^2$$}$$ at the surface.)

Accepted Answer

$$2.45\ \mathrm{m/s^2$}$$

Question 12

A $$3\ \mathrm{kg}$$ object is moving in a circle of radius $$0.5\ \mathrm{m} at a $$constant angular speed of $$4\ \mathrm{rad/s}. $$What is the magnitude of its centripetal acceleration?

Accepted Answer

$$16\ \mathrm{m/s^2$}$$

Question 13

A $$0.5\ \mathrm{kg}$$ mass oscillates on a spring with amplitude $$0.2\ \mathrm{m}$$ and period $$0.5\ \mathrm{s}. $$What is the maximum speed of the mass?

Accepted Answer

$$2.51\ \mathrm{m/s}$$

Question 14

A $$10\ \mathrm{kg}$$ box is pushed up a $$30^\circ$$ incline at constant speed. If the coefficient of kinetic friction is $$0.1$$, what is the required applied force parallel to the incline? (Use $$g = 9.8\ \mathrm{m/s^2$}.)$$

Accepted Answer

$$64.3\ \mathrm{N}$$

Question 15

A $$0.2\ \mathrm{kg}$$ puck slides on a frictionless surface and collides inelastically with a stationary $$0.3\ \mathrm{kg}$$ puck. If the $$0.2\ \mathrm{kg}$$ puck was moving at $$5\ \mathrm{m/s}$$ before the collision, what is the final velocity of the combined mass?

Accepted Answer

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

Question 16

A $$1\ \mathrm{kg}$$ mass is attached to a string and swung in a vertical circle of radius $$1\ \mathrm{m}. $$What is the minimum speed at the top of the circle so that the string remains taut?

Accepted Answer

$$3.13\ \mathrm{m/s}$$

Question 17

A $$0.5\ \mathrm{kg}$$ mass is attached to a spring and oscillates with a frequency of $$2\ \mathrm{Hz}. $$What is the spring constant $$k$$?

Accepted Answer

$$79\ \mathrm{N/m}$$

Question 18

A $$2\ \mathrm{kg}$$ object is moving at $$10\ \mathrm{m/s}$$ and collides head-on with a $$3\ \mathrm{kg}$$ object moving at $$-5\ \mathrm{m/s}. $$What is the velocity of the center of mass of the system?

Accepted Answer

$$0.4\ \mathrm{m/s}$$

Question 19

A $$1\ \mathrm{kg}$$ mass is attached to a string and spun in a horizontal circle of radius $$1\ \mathrm{m} at$$ $$2\ \mathrm{rev/s}. $$What is the tension in the string?

Accepted Answer

$$157.9\ \mathrm{N}$$

Physics 3A - Mechanics: Course Structure, Topics, and Study Guide

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