Forces (P8, P9 & P10) & Equations

Question 1

Write down the equation for WEIGHT

Answer 1

• Weight = mass x gravitational field strength
  W = m g

Question 2

Write the equation for WORK DONE

Answer 2

• work done = force x distance (moved along the line of action of the force)
  W = F s

Question 3

Write the equation for FORCE (spring one)

Answer 3

• Force = Spring constant x extension
  F = k e

Question 4

What is the equation for DISTANCE TRAVELLED?

Answer 4

• distance travelled = speed x time
  s = v t

Question 5

What is the equation for acceleration?

Answer 5

• acceleration = change in velocity / time taken
  v-u / t

Question 6

Equation for RESULTANT FORCE

Answer 6

• resultant force = mass x acceleration
  F = m a

Question 7

What is the equation for MOMENTUM?

Answer 7

• momentum = mass x velocity
  p = m v

Question 8

What is Newton’s First Law of Motion?

Answer 8

• If the resultant force acting on a STATIONARY object is zero, the object will remain stationary
• If the resultant force acting on a MOVING object is zero, the object will continue to move in the same direction at the same speed (with the same velocity)

Question 9

What is Newton’s Second Law of Motion?

Answer 9

The acceleration of an object is proportional to the resultant force acting on the object and inversely proportional to the mass of the object.

Question 10

What is the speed of an average car travelling in the UK on a main road?

Answer 10

~13 m/s

Question 11

What is the speed of an average car travelling in the UK on the motorway?

Answer 11

~30 m/s

Question 12

What is the acceleration needed for an average car in the UK to accelerate from a main road to a motorway?

Answer 12

A typical ~2/ms^2 is needed - this means for a typical family car, this would require a force of ~2000N

Question 13

What is Inertia?

Answer 13

Objects will stay still or keep the same motion unless you apple a resultant force.

Question 14

What is Inertial Mass?

Answer 14

The Inertial Mass is a measure of how difficult it is to change the velocity of an object.

Question 15

What is Newton’s Third Law of Motion?

Answer 15

When ever two (2) objects interact, the force they exert on each other are equal and opposite.