Q1: Calculate the acceleration of a bus that speeds up from 20 m/s to 40 m/s in 8 seconds
Given: u = 20 m/s, v = 40 m/s, t = 8 s
Formula: a = (v - u) / t
Solution: a = (40 - 20) / 8 = 20 / 8 = 2.5 m/s²
Answer: Acceleration = 2.5 m/s²
Formula: a = (v - u) / t
Solution: a = (40 - 20) / 8 = 20 / 8 = 2.5 m/s²
Answer: Acceleration = 2.5 m/s²
Q2: A bus is moving on a road with 15 m/s and it accelerates at 5 m/s². Find the final velocity after 6 seconds
Given: u = 15 m/s, a = 5 m/s², t = 6 s
Formula: v = u + at
Solution: v = 15 + 5 × 6 = 15 + 30 = 45 m/s
Answer: Final velocity = 45 m/s
Formula: v = u + at
Solution: v = 15 + 5 × 6 = 15 + 30 = 45 m/s
Answer: Final velocity = 45 m/s
Q3: A car starts moving from rest with an acceleration of 5 m/s². Find out the time to travel 50 m distance
Given: u = 0, a = 5 m/s², s = 50 m
Formula: s = ut + ½at² → 50 = 0 + ½×5×t² → 50 = 2.5t²
Solution: t² = 50 / 2.5 = 20 → t = √20 ≈ 4.47 s
Answer: t ≈ 4.47 seconds
Formula: s = ut + ½at² → 50 = 0 + ½×5×t² → 50 = 2.5t²
Solution: t² = 50 / 2.5 = 20 → t = √20 ≈ 4.47 s
Answer: t ≈ 4.47 seconds
Q4: A ball is dropped from a height of 50 m. What will be its velocity before touching the ground?
Given: u = 0, s = 50 m, a = g = 9.8 m/s²
Formula: v² = u² + 2as
Solution: v² = 0 + 2×9.8×50 = 980 → v = √980 ≈ 31.3 m/s
Answer: v ≈ 31.3 m/s
Formula: v² = u² + 2as
Solution: v² = 0 + 2×9.8×50 = 980 → v = √980 ≈ 31.3 m/s
Answer: v ≈ 31.3 m/s
Q5: An empty car has 1200 kg mass. Its engine can produce an acceleration of 4 m/s². If 300 kg load is added to mass by passengers and luggage, what acceleration will the same engine produce?
Given: Original mass m₁ = 1200 kg, a₁ = 4 m/s²
Total mass m₂ = 1200 + 300 = 1500 kg
Force of engine (F) = m × a = 1200 × 4 = 4800 N
Now for new mass: a₂ = F / m₂ = 4800 / 1500 = 3.2 m/s²
Answer: New acceleration = 3.2 m/s²
Total mass m₂ = 1200 + 300 = 1500 kg
Force of engine (F) = m × a = 1200 × 4 = 4800 N
Now for new mass: a₂ = F / m₂ = 4800 / 1500 = 3.2 m/s²
Answer: New acceleration = 3.2 m/s²
Q6: The mass of an object is 60 kg. Find its weight on:
i) Earth ii) Moon iii) Mars
Assume g on Earth = 9.8 m/s², Moon = 1.6 m/s², Mars = 3.7 m/s²
i) Earth ii) Moon iii) Mars
Assume g on Earth = 9.8 m/s², Moon = 1.6 m/s², Mars = 3.7 m/s²
Formula: Weight = mass × g
i) Earth: W = 60 × 9.8 = 588 N
ii) Moon: W = 60 × 1.6 = 96 N
iii) Mars: W = 60 × 3.7 = 222 N
i) Earth: W = 60 × 9.8 = 588 N
ii) Moon: W = 60 × 1.6 = 96 N
iii) Mars: W = 60 × 3.7 = 222 N
Q7: A car is running on a circular path of radius 1000 m. Mass = 600 kg, velocity = 72 km/h. Find:
i) Centripetal force ii) Centripetal acceleration
i) Centripetal force ii) Centripetal acceleration
Convert velocity: v = 72 km/h = 72 × 1000 / 3600 = 20 m/s
Given: m = 600 kg, r = 1000 m
Formula (i): Fc = mv² / r = 600 × 20² / 1000 = 240000 / 1000 = 240 N
Formula (ii): a = v² / r = 400 / 1000 = 0.4 m/s²
Given: m = 600 kg, r = 1000 m
Formula (i): Fc = mv² / r = 600 × 20² / 1000 = 240000 / 1000 = 240 N
Formula (ii): a = v² / r = 400 / 1000 = 0.4 m/s²
Q8: A block of mass 15 kg is pulled on a slippery floor. The spring balance shows force = 3 N. Find the coefficient of friction (F = ฮผmg)
Given: F = 3 N, m = 15 kg, g = 9.8 m/s²
Formula: F = ฮผmg → ฮผ = F / (mg) = 3 / (15 × 9.8) = 3 / 147 ≈ 0.0204
Answer: Coefficient of friction ≈ 0.0204
Formula: F = ฮผmg → ฮผ = F / (mg) = 3 / (15 × 9.8) = 3 / 147 ≈ 0.0204
Answer: Coefficient of friction ≈ 0.0204
