Forces and Motion

Question 1

Explain what is meant by a scalar quanitity

Answer 1

a magnitude - can be described with a single numerical value

Question 2

What are 2 examples of scalar quantities?

Answer 2

distance, speed, time, mass, energy

Question 3

Explain what is meant by a vector quantity

Answer 3

a magnitude and direction

Question 4

What are 2 examples of vector quantities?

Answer 4

force, velocity, displacement, momentum, moment

Question 5

How do you calculate speed from a distance-time graph?

Answer 5

the gradient

Question 6

What is the equation linking distance moved, time taken and average speed

Answer 6

speed = distance / time

Question 7

What is meant by acceleration?

Answer 7

the change in velocity per unit time

Question 8

What is the equation linking acceleration, change in velocity and time taken?

Answer 8

acceleration = change in velocity / time taken

Question 9

How do you calculate acceleration from a velocity-time graph?

Answer 9

gradient

Question 10

Which property of a velocity-time graph can be used to calculate the distance travelled?

Answer 10

area under the graph

Question 11

State the equation linking final speed, initial speed, acceleration and distance travelled

Answer 11

final speed^2 = initial speed^2 + (2 * acceleration * distance travelled)

Question 12

Name two forces which always oppose motion

Answer 12

Friction, Air Resistance (drag)

Question 13

What force holds planets around the sun?

Answer 13

gravitational

Question 14

What force holds electrons around the nucleus?

Answer 14

electrostatic

Question 15

State how a force can affect the body that it applied on

Answer 15

shape, speed, direction it is moving

Question 16

What is newtons second law?

Answer 16

F = ma (a resultant force means acceleration)

Question 17

What is newtons first law?

Answer 17

balanced forces mean no change in velocity - if it is stationary it will stay still, if it is moving it will carry on at the same velocity

Question 18

What is newtons third law?

Answer 18

if object A exerts a force on object B, then object B exerts an equal and opposite force on object A

Question 19

What is the relationship between stopping distance, braking distance and thinking distance

Answer 19

stopping distance = braking distance + thinking distance

Question 20

State 4 factors that affect the stopping distance of a car

Answer 20

reaction time, inital speed, road conditions, tire conditions, weather conditions, driver’s conditions, mass of the car

Question 21

State two factors that affect air resistance on a falling object

Answer 21

surface area, speed

Question 22

How does a falling object reach terminal velocity?

Answer 22

Object falls as a result of its weight, as it accelerates air resistance opposes the motion, therefore, resultant force decreases and since F=ma acceleration decreases

Question 23

What is Hooke’s law?

Answer 23

Extension is directly proportional to the force applied

Question 24

What is elastic behaviour?

Answer 24

an object recovers its original shape when the forces causing the extension are removed

Question 25

What is plastic behaviour?

Answer 25

there is a permenant deformation to the shape of the object when forces are removed