PS-10-Force Problems worksheet - Free Printable

Let's solve each problem step by step using Newton’s Second Law of Motion:

> F = m × a
> Where:
> - F = Force (in Newtons, N)
> - m = mass (in kg)
> - a = acceleration (in m/s²)

We'll use the triangle method as shown in the worksheet:
- If you cover F, you get m × a
- If you cover m, you get F ÷ a
- If you cover a, you get F ÷ m

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1. A 40-kg baseball is accelerated at 600 m/s² by what force?

Given:
- m = 40 kg
- a = 600 m/s²

Use:
F = m × a
F = 40 × 600 = 24000 N

✔ Answer: 24000

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2. The acceleration of gravity is 9.8 m/s² on Earth. An object has a mass of 700 kg. What is its weight?

Weight = Force of gravity = m × g
- m = 700 kg
- g = 9.8 m/s²

F = 700 × 9.8 = 6860 N

✔ Answer: 6860

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3. The weight of an object on a distant planet is 600 N, and its mass is 294.56 kg. What is the acceleration of gravity on that planet?

Given:
- F = 600 N
- m = 294.56 kg

Use:
a = F ÷ m
a = 600 ÷ 294.56 ≈ 2.04 m/s²

✔ Answer: 2.04

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4. A weightlifter raises a 500 kg barbell with an acceleration of 3 m/s². How much force does the weightlifter use?

The barbell must overcome gravity and accelerate upward.

So total force needed:
F = m × (g + a)
But wait — is this just net force or applied force?

Actually, the net force is:
F_net = m × a

But to lift it upward with acceleration, the applied force must be greater than weight.

So:
F_applied = m × (g + a)
= 500 × (9.8 + 3) = 500 × 12.8 = 6400 N

✔ Answer: 6400

*(Note: This assumes the question wants the total force applied by the lifter to accelerate it upward.)*

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5. If a 50 kg water rocket takes off with a force of 250 N, what is its acceleration?

Given:
- F = 250 N
- m = 50 kg

Use:
a = F ÷ m
a = 250 ÷ 50 = 5.00 m/s²

✔ Answer: 5.00

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6. A dancer lifts his partner above his head with an acceleration of 3 m/s². The dancer exerts a force of 175 N. What is the mass of his partner?

Given:
- F = 175 N
- a = 3 m/s²

But again, this force is applied upward, so we need to consider if gravity is involved.

The net force upward is:
F_net = m × a

But F_applied = m × (g + a), because he must lift against gravity and accelerate upward.

So:
F = m × (g + a)
175 = m × (9.8 + 3) = m × 12.8

Solve for m:
m = 175 ÷ 12.8 ≈ 13.67 kg

✔ Answer: 13.67

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✔ Final Answers:

1. 24000
2. 6860
3. 2.04
4. 6400
5. 5.00
6. 13.67

All answers are in correct units (N, m/s², or kg), and non-whole numbers are rounded to 2 decimal places, no commas used.

Let me know if you want the filled-in triangles!