Midterm Review #1

A boy on a skateboard throws a ball. The skateboard moves in the opposite direction from the thrown ball because:

• the skateboard resists acceleration due to Newton's 2nd Law

• the ball exerts a reaction force on the boy as it is being thrown

• the ball carries away some inertia

• the ball has positive energy, and the boy and the skateboard are left with negative energy

Which of these would have the greater inertia?

• a falling leaf

• a seated high school student

• a rising helium-filled toy balloon

• a softball in flight

Two apples accidentally fall out of an upstairs window of a house. One weighs twice as much as the other. The time it takes the heavier apple to hit the ground is:

• The same as the lighter apple

• Half the time as the lighter apple

• Twice the time a the lighter apple

• Just a little less time than the lighter apple

A person pulls a rope tied to a tree. If the person pulls the rope with a force of 120N, what is the reaction force on the rope?

• 0 N

• 240N in the same direction

• 120N in the opposite direction

• 120N in the same direction

If no forces are acting on an object or there is no net force, its motion will:

• slow down and eventually stop

• continue in the same direction with the same speed

• continue in the same direction but could change speed

• continue at the same speed but could change direction

A satellite weighs 200N on the surface of the Earth. What is its gravitational force at a distance of one Earth radius above the surface of Earth (ie, twice the distance)

• 50N

• 100N

• 400N

• 800N

A baseball player runs 27.4 m to 1st base, over runs it by 3 m, and then returns to it. What is the magnitude of the players DISTANCE from the batter's box.

• 24.4 m

• 30.4 m

• 27.4 m

• 33.4 m

An object is observed to have a acceleration of 2 m/s^2 when a net force of 4N is applied. The mass of the object is _.

• 0.5 kg

• 1.0 kg

• 2.0 kg

• 8.0 kg

You throw a softball straight up in the air. What’s the main force(s) acting on the ball after it leaves your hand?

• A downward force of gravity and an upward force that gets smaller and smaller.

• On the way up: an upward force that gets smaller and smaller. On the way down: a force of gravity.

• Only a downward force of gravity.

• No forces. The ball falls back to ground because that's its natural action.

While you’re slowly lifting a book straight upwards at a constant speed, the upward force of your hand on the book is:

• greater than the downward force of gravity on the book

• equal to the downward force of gravity on the book.

• smaller than the downward force of gravity on the book

• equal to the sum of the book’s weight and the force of gravity on the book