08 - Newtons Laws Practice Worksheet | PDF | Acceleration | Force - Free Printable

Let's solve this step by step.

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Part I: Fill in the blanks to state Newton’s three laws of motion

#### Newton’s 1st Law →
All objects will remain at rest, or will continue to move at a constant velocity in the same direction unless acted upon by an unbalanced force. This property is called inertia.

> ✔ *Explanation:* This is the law of inertia. Objects resist changes in their motion unless a net force acts on them.

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#### Newton’s 2nd Law →
Unbalanced forces cause an object to accelerate.
This can be stated mathematically by the formula:
F = m × a

> ✔ *Explanation:* Force equals mass times acceleration. The greater the mass or acceleration, the greater the force needed.

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#### Newton’s 3rd Law →
Every action produces an equal and opposite reaction.
When one object exerts a force on another object, the second object pushes back with the same amount of force.

> ✔ *Explanation:* Forces always come in pairs — for every action, there is an equal and opposite reaction.

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Part II: Use Newton’s 2nd Law (F = m × a) to solve each problem

We use the formula:
F = m × a
→ To find force: F = m × a
→ To find acceleration: a = F / m
→ To find mass: m = F / a

Let’s go through each question:

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#### 1) How much force is needed to accelerate a 66 kg skier at 2 m/s²?

Given:
m = 66 kg
a = 2 m/s²

F = m × a = 66 kg × 2 m/s² = 132 N

✔ Answer: 132 N

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#### 2) What is the force on a 1,000 kg elevator that is falling freely at 9.8 m/s²?

Free fall means it's accelerating due to gravity, so:
m = 1000 kg
a = 9.8 m/s²

F = m × a = 1000 kg × 9.8 m/s² = 9,800 N

✔ Answer: 9,800 N

> Note: This is the weight of the elevator (weight = mg), which is also the gravitational force acting on it.

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#### 3) What is the acceleration of a 50 kg object pushed with a force of 500 newtons?

Given:
F = 500 N
m = 50 kg

a = F / m = 500 N / 50 kg = 10 m/s²

✔ Answer: 10 m/s²

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#### 4) The mass of a large car is 1000 kg. How much force would be required to accelerate the car at a rate of 3 m/s²?

m = 1000 kg
a = 3 m/s²

F = m × a = 1000 kg × 3 m/s² = 3,000 N

✔ Answer: 3,000 N

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#### 5) A 50 kg skater pushed by a friend accelerates 5 m/s². How much force did the friend apply?

m = 50 kg
a = 5 m/s²

F = m × a = 50 kg × 5 m/s² = 250 N

✔ Answer: 250 N

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#### 6) A force of 250 N is applied to an object that accelerates at a rate of 5 m/s². What is the mass of the object?

F = 250 N
a = 5 m/s²

m = F / a = 250 N / 5 m/s² = 50 kg

✔ Answer: 50 kg

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✔ Final Answers Summary:

Part I:
- 1st Law: rest, velocity, direction, force, inertia
- 2nd Law: accelerate, F = m × a
- 3rd Law: reaction, force

Part II:
1) 132 N
2) 9,800 N
3) 10 m/s²
4) 3,000 N
5) 250 N
6) 50 kg

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