P10 Force And Motion

Question 1

Netwons First Law

Answer 1

If the resultant force on a stationary object is zero then the object will remain stationary. But if the resultant force on a moving object is zero then it will carry on moving at a constant velocity.

Question 2

Newton’s Second law

Answer 2

Resultant force = mass x acceleration

Force N
Mass kg
Acceleration m/s^2

Question 3

Newton’s Third Law

Answer 3

Whenever two objects interact, the forces they exert on each other are equal and opposite.

Question 4

What is Inertia?

Answer 4

• inertial mass is a measure of how difficult it is to change the velocity of an object
• inertial mass is defined as the ratio of force over acceleration.

Question 5

What is the difference between mass and weight?

Answer 5

Weight = mass x gravitational field strength

Question 6

Describe terminal velocity

Answer 6

An object falling through a fluid initially accelerates due to the forceof gravity. Eventually the resultant force will be zero and the object will move at its terminal velocity.

Question 7

Factors that affect Thinking Distance for braking?

Answer 7

Speed as you’ll travel further in the time taken to react

Reaction time

Question 8

Factors that affect Braking Distance in braking?

Answer 8

Speed
Weather
Road surface
Condition of tyres

Question 9

How does braking work?

Answer 9

When a force is applied to the brakes of a vehicle, work done by the friction force between the brakes and the wheel reduces the kinetic energy of the vehicle and the temperature of the brakes increases

Question 10

Equation for momentum

Answer 10

Momentum = mass x velocity

Momentum Kg m/s
Mass Kg
Velocity m/s

Question 11

In a closed system what happens to the momentum

Answer 11

Momentum before = momentum after

Question 12

Equation that links force, momentum and time

Answer 12

Force = change in momentum / change in time

Question 13

What is the difference between elastic deformation and inelastic deformation

Answer 13

In elastic deformation, the object will return to its original shape whereas in inelastic deformation it will not.

Question 14

What is hooks law

Answer 14

Force applied = spring constant x extension

Force N
Spring constant Nm
Extension m

Provided that the limit of proportionality is not exceeded

Question 15

Equation for braking force?

Answer 15

Braking force = mass x deceleration

or

Braking force = momentum / time

Question 16

How to calculate deceleration of a vehicle

Answer 16

V^2 = U^2 + 2as

a = deceleration 
U= initial velocity 
V= final velocity 
S= distance