Newtons 2nd Law Problems Worksheet - Science - Free Printable

Let’s solve each problem step by step using Newton’s 2nd Law:
Force = mass × acceleration → F = m × a
We can rearrange this to find any variable:
→ To find acceleration: a = F ÷ m
→ To find mass: m = F ÷ a
→ To find force: F = m × a

Also, for weight problems:
Weight (W) = mass × gravity → W = m × 9.8 m/s²
(Gravity on Earth is always 9.8 m/s² unless told otherwise.)

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Problem 1:
You push with 20 N. Mass = 60 kg. Find acceleration.
a = F ÷ m = 20 ÷ 60 = 0.333... → 0.33 m/s² (rounded to two decimal places)

Problem 2:
Force = 400 N, mass = 25 kg. Find acceleration.
a = 400 ÷ 25 = 16 m/s²

Problem 3:
Mass = 0.67 kg, acceleration = 5,600 m/s². Find force.
F = 0.67 × 5600 = let’s calculate:
0.67 × 5600 = (0.67 × 5000) + (0.67 × 600) = 3350 + 402 = 3752 N

Problem 4:
Mass = 88 kg, gravity = 9.8 m/s². Find force (weight).
F = 88 × 9.8 = let’s compute:
88 × 10 = 880, minus 88 × 0.2 = 17.6 → 880 - 17.6 = 862.4 N

Problem 5:
Mass = 53 kg, gravity = 9.8 m/s². Find weight.
W = 53 × 9.8 =
50 × 9.8 = 490, 3 × 9.8 = 29.4 → 490 + 29.4 = 519.4 N

Problem 6:
Mass = 75 kg. Find weight.
W = 75 × 9.8 =
75 × 10 = 750, minus 75 × 0.2 = 15 → 750 - 15 = 735 N

Problem 7:
Mass = 0.77 kg. Find weight.
W = 0.77 × 9.8 =
0.77 × 10 = 7.7, minus 0.77 × 0.2 = 0.154 → 7.7 - 0.154 = 7.546 N → round to 7.55 N

Problem 8:
Mass = 20 kg, acceleration = 10.0 m/s². Find force.
F = 20 × 10.0 = 200 N

Problem 9:
Mass = 2.4 × 10³ kg = 2400 kg, Force = 3.2 × 10³ N = 3200 N. Find acceleration.
a = F ÷ m = 3200 ÷ 2400 = 32 ÷ 24 = 4 ÷ 3 ≈ 1.33 m/s²

Problem 10:
Mass = 100 kg, acceleration = 4 m/s². Find force.
F = 100 × 4 = 400 N

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Final Answer:
1. 0.33 m/s²
2. 16 m/s²
3. 3752 N
4. 862.4 N
5. 519.4 N
6. 735 N
7. 7.55 N
8. 200 N
9. 1.33 m/s²
10. 400 N