Unit 1&2 - Forces & Motion

Question 1

What is a scalar quantity and what is an example?

Answer 1

Any quantity that has magnitude e.g. time, distance

Question 2

What is a vector quantity and what is an example?

Answer 2

Any quantity that has magnitude and direction e.g. velocity, acceleration, force

Question 3

What is the resulting force and the direction?

• ——>E + —–>E
  46. 5m 20m

Answer 3

66.5m ——–>East

Question 4

A man travels 120km East then 160km north.

What is the resultant distance?

Answer 4

R=√(160^2+120^2 )

R=200km

Question 5

What does the gradient of a displacement(s) / time(s) graph mean?

Answer 5

Velocity

Question 6

What does the gradient of a velocity(m/s) / time(s) graph mean?

Answer 6

Acceleration

Question 7

What are Newton’s 3 laws (simplified)?

Answer 7

1) Inertia
2) F=ma
3) action/reaction

Question 8

What is momentum and what is the equation for momentum?

Answer 8

1) Mass in motion

2) Momentum(p)=mass(kg) x velocity(m/s)

Question 9

What are the 2 equations for the change in momentum?

Answer 9

1) ∆p=Change in force(F∆=N) x time(s)

2) ∆p=mass(kg) x final velocity(m/s) - mass(kg) x initial veloctiy(m/s)

Question 10

What is Potential energy and what is the equation for it?

Answer 10

1) The energy an object possesses in relation to another object(usually the earth) due to gravity
2) Potential Energy(PE=J) = mass(kg) x gravity(m/s/s) x height(m)

Question 11

What is Kinetic energy and what is the equation for it?

Answer 11

1) The energy an object possesses due to being in motion

2) Kinetic Energy(KE=J) = 1/2 x mass(kg) x velocity(m/s)^2

Question 12

What is the equation for work at angled forces?

Answer 12

Work(Nm)=(Force(N) x cos(θ)) x distance(m)

Question 13

What is the equation for efficiency?

Answer 13

Efficiency = Energy Output/Energy Input x 100%