Unit 1 Module 1 - Newton's Law and Momentum

Question 1

What is Newton’s first law?

Answer 1

Newton’s first law states that a force is necessary to change the state of rest or uniform motion in a straight line of a body

Question 2

When must a resultant force act on you?

Answer 2

To change direction, go from stationary to having motion and to speed up or slow down

Question 3

When you are moving with constant velocity, is there a restultant force?

Answer 3

No

Question 4

Why do you feel heavier in a lift when it is going up?

Answer 4

The lift is accelerating so the force exerted on your feet is greater than your weight

Question 5

Why do you feel lighter in a lift when it is going down?

Answer 5

The force from the lift to the feet is less than your weight

Question 6

What is Newton’s second law of motion?

Answer 6

The rate of change of the momentum of an object is directly proportional to the resultant force acting upon it

Question 7

What is the equation demonstrating the second law of motion?

Answer 7

change in momentum/ time interval is directly proportional to force

Question 8

How is the second law of motion derived from the F=ma equation?

Answer 8

F=ma
F=m x (v-u)/t
F=(mv-mu)/t

Question 9

What is one newton?

Answer 9

One newton is the force that fives a mass of 1kg an acceleration of one metre per second each second

Question 10

How is the k constant in the kF proportional ma found?

Answer 10

The definition of one newton gives the constant a number of 1

Question 11

What is mass?

Answer 11

The inertia of an object, or how difficult it is to accelerate the object

Question 12

What is weight?

Answer 12

The gravitational force the Earth exerts on an object

Question 13

What is Newton’s third law?

Answer 13

When a body A exerts a force on body B, then body B exerts on body A a force that is equal, oppsite in direction and of the same type. This means that the reaction force must be a gravitational force if the original force was a gravitational force

Question 14

What is the conservation of momentum originated from?

Answer 14

Newton’s third law - if the forces in a collision are equal and opposite then the loss of momentum in one object is equal to the gain in momentum of the other object.

Question 15

What is the principle of conservation of momentum?

Answer 15

In any direction, in the absence of external forces, the total momentum of a system remains constant.

Question 16

What is impulse?

Answer 16

It is defined by the expression force x change in time. It equals the change in momentum of a body. It is equal to the area beneath a force-time graph

Question 17

What is an perfectly elastic collision?

Answer 17

One where no momentum or kinetic energy is lost. These are soundless collisions.

Question 18

What is an inelastic collision?

Answer 18

Momentum is conserved, but kinetic energy is lost. The energy is transferred into sound of heating energy.

Question 19

What is a perfectly inelastic collision?

Answer 19

After a collison the two objects are stuck together

Question 20

What does the term ‘superelastic’ mean?

Answer 20

There is more energy after a collision than before it, this means that energy is supplied into the collision