Newton’s Second Law (well mostly!)

How does inertia act on an object that is moving in a circle?

• It directs the object to the center of the curve.

• It causes the object to speed up as it turns.

• It causes the object to move along a straight path.

• It causes the object to continue to spin

A ball held in a person’s hand does not move even though gravity is acting on it because———.

• The force of gravity creates a net unbalanced force.

• The force of gravity is not strong enough to move the ball.

• The force of gravity is balanced by the upward force exerted by the hand.

• The force of gravity is less than the force exerted by the hand.

According the Newton’s second law of motion, which equation determines the acceleration of an object?

• a = F/m

• a = m/F

• N = m/a

• a = m x F

Only ——— forces change an object’s velocity.

• Strong

• Unbalanced

• Net

• Balanced

Calculate the acceleration of an object with a mass of 2kg and a force of 30N acting on it.

• 15 m/s²

• 60 m/s²

• 30N

• 32 kg

Which is NOT a way an unbalanced force can affect the motion of an object.

• Change its speed

• Remain at constant speed in a straight line

• Change its direction

• Change its speed and direction

What happens to the speed of an object if the net force is opposite the direction of motion?

• The object speeds up.

• The object slows down.

• No change because it’s a balanced force.

• The object does not accelerate.

An object's velocity can be changed by changing its speed, its direction, or both.

• True
• False

If a force of 26 N is exerted on two balls, one with a mass of 0.52 kg and the other with a mass of 0.78 kg, which ball will have the greater acceleration?  (F=ma)

• The one with a mass of .78 kg will have the greatest acceleration.
• The one with a mass of .52 kg will have the greatest acceleration.
• They will both accelerate at the same rate.

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According to Newton’s third law of motion, when a hammer strikes and exerts force on a nail, the nail

• creates a friction with the hammer.

• disappears into the wood.

• exerts an equal and opposite force on the hammer.

• moves at a constant speed.

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