Force and motion Quiz 2

6.8C- An airplane leaves New York to fly to Boston. It travels 1,000 km in 2 hours. What is the average speed of the airplane?

• 500 km

• 1000 hours

• 500 km/hour

• 5000 hours/km

What is Newton's first law of motion?

• Every action has an equal opposite reaction

• An object in motion stays in motion unless acted upon by an unbalanced force

• The force acting on an object is equal to the mass of an object times its acceleration

• Sandwich

Safety belts protect people in cars in the event of an accident because, according to Newton’s Laws of Motion, when an impact causes the car to suddenly change its motion, -

• the people in the car will continue to move in the same direction and at the same speed as before the impact.
• the speed of the car always increases, giving it greater force since the mass will remain the same.
• the speed of the people always increases, since now they have, not one, but two forces acting on them.
• the car now has a greater overall mass - its own mass plus the mass of the object by which it has been struck.

A ball thrown into the air starts out with an initial upward velocity, but eventually slows and stops before falling back to the ground. Which of the following contributes the most to the change in motion of the ball?

• The initial force with which the ball is thrown
• The downward force of gravity
• The resistance against the atmosphere
• The increase of inertia

The illustration provided shows two boys pulling on opposite ends of a rope with different amounts of force. The net force is 10 N right. (true or false)

• True

• False

For an object to remain at rest, which of the following must be true?

• The forces on it are balanced.

• There is no friction.

• Gravity does not act on it.

• The object has no mass.

If an object increases in speed, it must be as a result of

• increasing friction.

• unbalanced forces.

• gravitational attractions.

• air resistance.

Which of the following examples accurately describes an object that is accelerating?

• A ball sitting motionless on the floor.

• An airplane moving at 500 kilometers per hour.

• A car slows down to turn a sharp corner.

• A bike moving backward at 3 meters per second.

How much force (newtons) is required to accelerate a 2.55 kg remote-controlled toy car at a rate of 6.00 m/s²?

• 15.3

• 2.35

• 8.55

• 3.45

Newton's third law states that any action will have a(n) _______ and ______ reaction

• equal and same

• equal and opposite

• equal and equal to