Newton's Laws review game

If the gravity disappears when an object is in free fall, what will happen?

• Floats in the air and stay still

• The speed decreases

• Keep going down at a constant speed

• We don't know

A car is moving in a straight line in an east-west direction, there is a wooden block on it. Suddenly, the block falls westward. What is the possible movement of the car?

• Moving to the east at a great and constant speed

• Moving to the east at a decreasing speed

• Moving to the east at a increasing speed

• Moving to the west at a increasing speed

What is correct about inertia?

• An object in the space does not have inertia

• All objects have inertia

• Heavier objects have less inertia

• We wear seat belts to reduce inertia

A traveller jumps on the deck(甲板). Where will this traveller land?

(ignore air resistance) (reference the DECK参照甲板）

• In front of the jumping point

• At the jumping point

• Behind the jumping point

• We don't know

If a man jumps from a moving car, then he will

• Fall in the direction of the moving car

• Fall in the opposite direction of the moving car

• Fall to the right

• Fall to the left

On a rough surface, an object's mass is m. Someone exerts a horizontal force F to push it, then causes an acceleration of a. The friction force on the object is F₁. If F changes to 2F, what will happen?

• The acceleration is still a

• The acceleration changes to 2a

• The friction force is still F₁

• The friction force changes to 2F₁

A man of mass m is standing in an elevator. The elevator is going up with an increasing speed. The acceleration is 1/3g, g is gravity acceleration. The man's pressure on the bottom of the elevator is

• mg

• 1/3mg

• 2/3mg

• 4/3mg

A mass which weighs 2kg is on a smooth surface. When we pull it with a force F=10N, so what the acceleration will be

• 5m/s²

• 0.2m/s²

• 20m/s²

• 12m/s²

When we push a table but it does not move, it's probably because

• The acceleration of the table is too small to be observed

• The force we exert is smaller than the friction. So the acceleration is less than 0

• The net force(合力) of all the forces is zero, so the acceleration is 0

• Physics cannot explain it :(

An object which weighs 1kg is moving up with an increasing speed. The acceleration of it is 7m/s², the resultant force on the object is

• 3N

• 7N

• 13N

• 17N