P10) Force And Motion

Question 1

What does Newton’s second law of motion say the acceleration of an object is?

Answer 1

1) proportional to resultant force on object.

2) inversely proportional to mass of object

Question 2

How do you calculate the resultant force on an object from its acceleration and its mass?

Answer 2

Resultant force, F (newtons, N) = mass, m (kilograms, kg) * acceleration, a (metres per second, m/s**2).

Question 3

What is the inertia of an object?

Answer 3

The tendency of object to stay at rest or to continue in uniform motion (e.g. moving at constant velocity).

Question 4

What is the inertial mass of an object?

Answer 4

Measure of difficulty of changing object’s velocity.

Question 5

What can inertial mass be defined as?

Answer 5

Force ÷ acceleration.

Question 6

What us the mass of an object?

Answer 6

Force acting on it due to gravity.

Question 7

What does the mass of an object depend on?

Answer 7

Quantity of matter in it.

Question 8

What is mass measured in?

Answer 8

Kilograms, kg.

Question 9

What is the weight of an object measured in?

Answer 9

Newtons, N.

Question 10

What is the gravitational force on an 1kg object?

Answer 10

Gravitational field strength at place where object is.

Question 11

What is gravitational field strength measured in?

Answer 11

Newtons per kilogram (N/kg).

Question 12

What is the equation for calculating the force due to gravity which acts on it if we know the mass?

Answer 12

Weight, W (newtons, N) = mass, m (kilograms, kg) * gravitational field strength, g (newtons per kilogram, N/kg).

Question 13

What is the terminal velocity of an object?

Answer 13

When object reaches constant velocity when frictional force on it is equal + opposite to its weight.

Question 14

What is stopping distances in a driving test?

Answer 14

Shortest distance a vehicle can safely stop in, + is in 2 parts.

1) thinking distance.
2) braking distance.

Question 15

What is thinking distance?

Answer 15

Distance travelled by vehicle in time takes driver to react (e.g. during drivers reaction time).

Question 16

What is the braking distance?

Answer 16

Distance travelled by vehicle during time braking force acts.

Question 17

What is the relationship between the speed, reaction time and thinking distance?

Answer 17

Thinking distance = speed * reaction time.

Question 18

What is the equation for calculating the momentum of a moving object?

Answer 18

Momentum of moving object, p (kg m/s) = mass, m (kg) * velocity, v (m/s).

Question 19

If an object is elastic does it go back to its original shape?

Answer 19

Yes.

Question 20

If an object doesn’t return to its original shape after being deformed what is it said to have been?

Answer 20

Inelastically deformed.

Question 21

What is Hooke’s law?

Answer 21

Extension of a spring directly proportional to force applied, as long as limit of proportionality not exceeded.

Question 22

What is Hooke’s law written as an equation?

Answer 22

Force applied, F (newtons, N) = spring constant, k (newtons per metre, N/m) * extension, e (metres, m).