Force and Motion

Question 1

What does a horizontal line represent on a graph of displacement against time?

Answer 1

A stationary object

Question 2

What does a line with a constant gradient represent on a graph of displacement against time?

Answer 2

An object with constant velocity

Question 3

What does a curved line represent on a graph of displacement against time?

Answer 3

Acceleration or deceleration

Question 4

What does a horizontal line represent on a graph of displacement against time

Answer 4

An object with a constant velocity

Question 5

What does a line with a constant gradient represent on a graph of displacement against time?

Answer 5

The constant acceleration of the object for a positive gradient or constant deceleration for negative gradient

Question 6

What does the area under a velocity-time and acceleration-time graph represent?

Answer 6

The displacement of the object and the change in velocity respectively

Question 7

Describe how the terminal velocity of an object can be determined using light gates?

Answer 7

• light gates are connected to a timer or data logger
• the time when each of the two beams are broken by the object and the time difference (with a number of repeats done to improve accuracy) combined with the known distance between the light gates are used to find the velocity
• velocity = distance / time

Question 8

Meaning of scalar quantity

Answer 8

Only magnitude but not direction

Question 9

Meaning of vector quantity

Answer 9

Magnitude and direction

Question 10

Acceleration vector or scalar?

Answer 10

Vector

Question 11

Mass scalar or vector

Answer 11

Scalar

Question 12

Newton’s third law

Answer 12

Every action force has an equal and opposite reaction force

Question 13

Newton’s second law

Answer 13

An object will accelerate in response to a resultant force

Question 14

Newton’s first law

Answer 14

An object will remain its inertia until a net force is acted on the object.

Question 15

Difference between elastic and in elastic collisions?

Answer 15

Elastic collision: kinetic energy before is equal to the kinetic energy afterwards
Inelastic collision: kinetic energy at the end is not equal to the kinetic energy at the start

Question 16

Is linear momentum only conserved in elastic collisions

Answer 16

No, it is because linear momentum is always conserved

Question 17

What can be described as the rate of change of momentum?

Answer 17

Force

Question 18

Work done definition

Answer 18

Work done is the product of the magnitude of the force and distance moved by the object in the direction of the force. It is a measurement of energy and it’s units are joules with SI base unit kgm^2 s^-2

Question 19

Rate of work done equal to

Answer 19

Power

Question 20

Meaning of principle of conservation of energy

Answer 20

Energy cannot be created or destroyed, it can on,y be transferred into other forms of energy. The total energy in a closed system will always remain the same.

Question 21

Definition of kinetic energy

Answer 21

The energy associated with the motion of an object with mass. The SI base unit is kgm^2s^-2

Question 22

Definition of gravitation potential energy

Answer 22

The energy stored by an object at a point in a gravitational field.

Question 23

Definition of elastic potential energy

Answer 23

The energy stored by an object as a result of a reversible change in an object’s shape

Question 24

Efficiency

Answer 24

Useful/input * 100%

Question 25

What is a moment? State the principle of moments

Answer 25

A turning force
Moment = force * perpendicular distance from the object
For an object in equilibrium the sum of the clockwise moments will equal the sum of the anti-clockwise moments.

Question 26

Where is the “centre of gravity” on a uniform object

Answer 26

At its geometrical centre