Friction
What force resists motion when two surfaces slide past each other?
Friction
What is the unit of work?
Joule (J)
What quantity is the product of mass and velocity?
Momentum
What is change in the horizontal velocity of a projectile (neglecting air resistance)?
It remains the same
What is the value of earth's gravitational field near the surface?
9.8 N/kg
What happens to the force of friction if the normal force increases?
The friction force increases
How much work is done when a 10 N force moves an object 2 m in the direction of the force?
20 J
What happens to the momentum of an object if its velocity doubles?
The momentum doubles
Which component of a projectile’s velocity is affected by gravity?
The vertical component
How does gravitational field strength change as distance from Earth increases?
It decreases
A box slides at constant velocity across a rough floor. How does the friction force compare to the applied force?
The friction force is equal in magnitude to the applied force
How much kinetic energy does a 2 kg object have when moving at 3 m/s?
9 J
A 1 kg cart moving at 4 m/s collides and sticks to a 1 kg cart at rest. What is conserved?
Momentum
A ball is thrown horizontally from a cliff. What is its initial vertical velocity?
0 m/s
What happens to an object’s weight if it is moved to a planet with a smaller gravitational field strength?
The object’s weight decreases
What happens to friction if the surface area of contact increases (same materials, same normal force)?
It stays the same
How much power is used if 600 J of work is done in 3 seconds?
200 W
What impulse is required to change the momentum of an object by 10 kg·m/s?
10 kg·m/s
A projectile is launched at an angle. At what point is its vertical velocity zero?
At the highest point (top of the trajectory)
How does gravitational field strength relate to weight and mass?
Fg = mg,
A 5 kg box is pulled with a force of 40 N and moves at constant velocity. What is the magnitude of the friction force?
40 N
A 2 kg object falls from rest. What is its kinetic energy after falling 5 m (neglect air resistance)?
98 is J
A 0.5 kg ball rebounds off a wall with the same speed it hit. How does the magnitude of its momentum change?
The magnitude of the momentum remains the same
Two projectiles are launched horizontally at the same time from the same height, one faster than the other. Which hits the ground first?
They hit the ground at the same time
How does gravitational field strength depend on the mass of a planet and the distance from its center?
It increases with mass and decreases with distance (inverse-square relationship)