Forces

Question 1

Equation for Speed

Answer 1

speed = distance / time

Question 2

Typical walking speed

Answer 2

1.4 m/s

Question 3

Typical running speed

Answer 3

3.3 m/s

Question 4

Typical wind speed

Answer 4

6 m/s

Question 5

Typical speed of bus in town

Answer 5

10 m/s

Question 6

Typical speed of sound

Answer 6

330 m/s

Question 7

Typical speed of car on motorway

Answer 7

31 m/s

Question 8

Equation for Acceleration

Answer 8

acceleration = change in velocity / time taken

Question 9

Equation for Moment

Answer 9

moment = force x perpendicular distance

Question 10

Equation for Force (moment)

Answer 10

force = moment / perpendicular distance

Question 11

Equation for Pressure

Answer 11

pressure = force / area

Question 12

Equation for Pressure in liquids

Answer 12

pressure beneath the surface = density × gravitational field strength × depth

Question 13

What is Upthrust

Answer 13

upward force exerted by a fluid that opposes the weight of a object

Question 14

When does an object float ?

Answer 14

If the object’s weight is equal to the upthrust, then the forces balance and the object will float in the liquid.

Question 15

When does an object sink ?

Answer 15

If object’s weight is greater than the upthrust, then the object will sink.

Question 16

Pressure Difference

Answer 16

pressure difference=density of fluid×gravitational field strength×change in depth

Question 17

Weight

Answer 17

is the force that acts on an object in a gravitational field

weight = mass x gravitational field strength

Question 18

Resultant Force

Answer 18

Resultant Force = forces acting in one direction−forces acting in the opposite direction

Question 19

Newton’s 2nd Law

Answer 19

resultant force = mass x acceleration

Question 20

Hooke’s Law

Answer 20

force = spring constant x spring extension

Question 21

Elastic Potential Energy Stored in a Spring

Answer 21

E = 1/2 x spring constant x extension²

Question 22

Equation for Spring Extension

Answer 22

spring extension = force applied / spring constant

Question 23

Equation for Momentum

Answer 23

momentum = mass x velocity

Question 24

Equation for Force when given change in momentum

Answer 24

force = change in momentum / time

Question 25

Equation for Work Done

Answer 25

work done = force x distance

Question 26

Newton’s Third Law

Answer 26

whenever two objects interact, they exert equal and opposite forces on each other.

Question 27

Newtons’s First Law

Answer 27

an object remains in the same state of motion unless a resultant force acts on it.

If resultant force zero:

• a stationary object stays stationary
• a moving object continues to move at the same velocity (at the same speed and in the same direction)