Newton’s First And Second Law

Question 1

What does Newton’s First Law state about the resultant force on an object?

Answer 1

an object requires a resultant force to change to make it slow down, start moving or speed up

Question 2

What happens to a stationary object if the resultant force acting on it is zero?

Answer 2

it remains stationary

Question 3

What happens to a moving object if the resultant force acting on it is zero?

Answer 3

it continues moving at the same velocity.

Question 4

What conditions must be met for a train, car, or any moving object to maintain a constant velocity?

Answer 4

the resistive and driving forces acting on it must be balanced

Question 5

What does a non-zero resultant force always produce in an object?

Answer 5

It always results in acceleration or deceleration in an object.

Question 6

What are the five forms of acceleration mentioned in the context of non-zero resultant force?

Answer 6

starting, stopping, speeding up, slowing down, and changing direction.

Question 7

What is the relationship between the resultant force acting on an object and its acceleration?

Answer 7

The force and acceleration are directly proportional- The larger the resultant force acting on an object, the more it accelerates.

Question 8

How does the mass of an object affect its acceleration?

Answer 8

Acceleration is inversely proportional to the mass of the object, meaning that an object with a larger mass will accelerate less than one with a smaller mass, given a fixed resultant force.

Question 9

What formula describes Newton’s Second Law?

Answer 9

Resultant force(N)= acceleration (m/s^2) x mass (kg)

Question 10

A van of mass of 2080 kg has an engine that provides a driving force of 5200 N.
At 70 mph the drag force acting on the van is 5148 N. Find its acceleration at 70 mph.

Answer 10

1) Work out the resultant force on the van.(Drawing a free body diagram may help.)
2) Rearrange F = ma and stick in the values you know

Ans: Resultant force = 5200 - 5148 = 52 N
a = F ÷ m
= 52 + 2080 = 0.025 m/s

Question 11

Estimate the resultant force on a car as it accelerates from rest to a typical speed.

Answer 11

1)Estimate the acceleration of the car, using typical speeds from page 207.
(The ~ means approximately.)
2) Estimate the mass of the car.
3) Put these numbers into Newton’s 2nd Law.