Linear Motion and Force

Question 1

Define Vector

Answer 1

A vector is a quantity that has both direction and magnitude.

Some examples may be:

• Displacement
• Velocity
• Acceleration
• Force

Question 2

Define Scalar

Answer 2

A scalar is a quantity that has only magnitude.

Some examples may be:

• Distance
• Speed
• Mass
• Time

Question 3

Define Displacement

Answer 3

The change of position of an object in a given direction away from an origin.

Question 4

Define Velocity

Answer 4

Velocity is the rate of change of the displacement of an object.

Question 5

Define Acceleration

Answer 5

Acceleration is the rate of change of the velocity of an object

Question 6

What is the acceleration due to Gravity?

Answer 6

The acceleration of free-falling objects on earth is 9.8ms^-2

Question 7

Compare and contrast average and instantaneous velocity

Answer 7

Average and Instantaneous velocity are similar in that they both measure the rate of change of the position of the object, but it is the time period over which they are different. Instantaneous velocity is measured over an instantaneous interval, whereas average velocity is measured over a period of time.

Question 8

Define Newtons three laws of Motion and give examples of each.

Answer 8

1. The law of inertia states that objects at rest and objects in motion will stay in motion unless acted upon by an outside force. If a ball was thrown into the vacuum of space, it would continue on forever unless something stopped it.
2. Force equals mass multiplied by acceleration. If a ball of 5kg was accelerated at 5ms^-2, the ball would have a force of 25kg/m/s^2 ( or Newtons)
3. every action has an equal and opposite reaction that is equal in strength and opposite in direction.

Question 9

Define Momentum

Answer 9

Momentum is the product of ones mass and its velocity.

Question 10

Define impulse

Answer 10

Impulse is the change of momentum of an object, which is the product of a force over an interval of time in which that force acts.

Question 11

Recall the conservation of momentum

Answer 11

The conservation of momentum states that for two objects in an isolated system, the total momentum before and after the colision is zero.

Question 12

Define the normal force

Answer 12

The normal force is a contact force that is perpendicular to the contacting objects.

Question 13

What is the gradient of a displacement-time graph and a velocity time graph equal to?

Answer 13

Gradient of a displacement-time graph = Velocity

Gradient of a velocity-time graph = Acceleration

Question 14

What is the area under a velocity-time graph and an acceleration time graph equal to?

Answer 14

The area under a velocity-time graph = Displacement

Area under an acceleration time graph = Velocity

Question 15

What is the area under a force-time graph equal to?

Answer 15

The area under a force-time graph = impulse.

Question 16

Define Mechanical Work

Answer 16

the product of the force and the displacement in the direction of an applied force.

Question 17

Define Kinetic Energy

Answer 17

Kinetic energy is the energy due to the motion of an object

Question 18

Define gravitational potential energy

Answer 18

Gravitational Potential Energy is the energy stored in an object due to its position relative to another object in a gravitational field.

Question 19

What is the area under a force-displacement graph equal to?

Answer 19

Area under a force-displacement graph = Work

Question 20

Define an Elastic and an Inelastic collision

Answer 20

An elastic collision is a collision where the kinetic energy and the momentum are conserved.

An inelastic collision is a collision where the kinetic energy is not conserved, but the momentum is conserved.

Question 21

Compare and contrast elsatic and inelatic collisions

Answer 21

Both elastic and inelastic collisions maintain the conservation fo momentum, however only the elastic collisions conserve kinetic energy before and after the collision.