Forces & Motion

Question 1

How do you calculate speed

Answer 1

speed = distance / time

Question 2

What is the normal unit for speed?

Answer 2

Metres per second - m/s

Question 3

What does velocity mean?

Answer 3

speed of something and its direction of travel

Question 4

How is velocity shown?

Answer 4

speed and arrow for direction, for motion in a straight line left or right you can show this with + or -. + travelling to the right and - travelling to the left.
e.g + 10m/s means a velocity of 10 m/s to the right.

Question 5

Changing velocity can be described as?

Answer 5

Acceleration

Question 6

What is the formula for acceleration

Answer 6

average acceleration = change in velocity/time taken

a = v - u
____
t

Question 7

A car passes post A with a velocity of 12 m/s. if it has a steady acceleration of 3 m/s2, what is its velocity 5 seconds later at a second post B?

Answer 7

The car is gaining 3m/s of velocity every second. so in 5 seconds it gains an extra 15 m/s on top of the original 12 m/s. Therefore its final velocity at B is 27 m/s.

Final velocity = original velocity + extra velocity

Question 8

What symbol represents the acceleration of free fall?

Answer 8

g

g = 9.8 m/s

Question 9

Is g the same all over he planet

Answer 9

There are small variations of up to 1%.
g is 9.8 m/s close the the Earth’s surface as you move away from Earth and out into space it decreases as the gravitational pull of the Earth decreases.

Question 10

What is a force?

Answer 10

A push or a pull.

Question 11

What is the unit of force?

Answer 11

a Newton (N)

Question 12

What machine us used to measure Newtons?

Answer 12

a spring balance / Newton meter.

Question 13

Give 6 common examples of forces?

Answer 13

Upthrust - upwards force from a gas or liquid that makes thing float

Tension - Force in a stretched material

Friction - The force that opposes the motion of one material sliding past the other

Air resistance - a type of friction

Thrust - The forward force from an aircraft

Weight - The gravitational force on an object

Question 14

What is Sir Isaac Newton’s first law of motion?

Answer 14

If no external force is acting on it, an object will:

• if stationary, remain stationary
• if moving, keep moving at a steady speed in a straight line

(On Earth friction and gravity will cause an unpowered object to come to rest.)