Unit 3 Forces - AP Physics 1

If no forces are acting on an object, its motion will

continue in the same direction with the same speed.

If an object changes its direction of motion

a force must have been applied to the object.

What kind of relationships is there between Force, Mass, and Acceleration?

Accel=Force/Mass

What would a free body diagram look like for a ball thrown up for all vectors acting on it.

Speed=Up, Force=Down, Accel=Down

Which force always opposes the motion of the object?

Friction

The inertia of an object comes from its

mass

What is the acceleration of gravity on the moon if a rock is 50 kg and weighs about 75 N.

1.6 m/s²

You push on your book to the right with 10 N, what is the force to the left if no movement?

10 N

The normal force is

The force acting perpendicular to the surface

You push a block across the table with 1 N at constant speed. The m-block= 0.1 kg, what is μ?

1

You (1000 kg) sit in your chair. How much force does each of the 4 legs need exert down.

250 N each

An object is in equilibrium when

the net force on the object is zero

A person waterskiing is towed behind a boat at a constant speed. You impress people by saying:

The friction of the water matches the tension in the rope

You push your friend on roller blades with a force of 200 N. What is their acceleration?

not enough info

If the net force is negative and the speed is positive

the speed will decrease over time

When you kick a ball, foot feels the ball because

the harder you kick the ball, the harder it kicks you back

You’re stranded in the middle of a frozen pond. What do you do to save your life?

Throw your physics book

A block is stationary on 30 degree ramp because F(gx) balance of F(f). Which statement is also true?

FN balances Fgy

A 100 lbs person weighs 200 lbs in an elevator... what must be happening to the elevator?

accelerating up at 9.81 m/s²

Which of the following situations MUST have a net force?

An object accelerates from 1 m/s to 2 m/s

Gary (50kg) is snowboarding down a 30 ∘ hill at a constant speed. What is the frictional force?

250 N

If every force has an equal and opposite reaction, why don;t all forces cancel each other out?

The action/reaction forces act on different objects

The coefficient of static friction is:

larger than the coefficient of sliding friction

If you have a constant speed of 4 m/s you can conclude that:

The total net force acting on the object is zero.