ECAT — Engineering College Admission Test (UET)
Take the ECAT Physics — Motion, Force and Momentum (Set 7): 30 multiple-choice questions (40 minutes) with instant scoring and a full answer review.…
What this test covers
The first 5 questions of this test, with the correct answer and explanation.
Q1. A tram's velocity rises uniformly from 0 to 12 m/s in 4 s, stays constant for 6 s, then falls uniformly to zero in 2 s. The total distance covered is:
Answer: B. 108 m
Explanation: Areas under the v–t graph: ½(4)(12) + (6)(12) + ½(2)(12) = 24 + 72 + 12 = 108 m.
Q2. A car moving at speed v on a level road brakes to rest with constant retardation in a distance s. If the same car, with the same retardation, starts at speed 2v, the stopping distance is:
Answer: B. 4s
Explanation: From v² = 2as, s ∝ v², so doubling the speed multiplies the distance by 4.
Q3. A train decelerates uniformly from 20 m/s to rest in a distance of 100 m. The time taken is:
Answer: C. 10 s
Explanation: s = ½(u + v)t so 100 = ½(20)t, t = 10 s.
Q4. A body starts from rest with a constant acceleration of 4 m/s². The distance it covers during the 5th second of its motion is:
Answer: C. 18 m
Explanation: s_n = ½a(2n − 1) = ½(4)(9) = 18 m (50 m is the distance in 5 s).
Q5. A stone is thrown vertically upwards at 20 m/s from the edge of a 25 m cliff and finally lands on the ground at the foot of the cliff. Taking g = 10 m/s², the time of flight is:
Answer: A. 5 s
Explanation: Taking up as positive: −25 = 20t − 5t², so t² − 4t − 5 = 0 and t = 5 s.
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Q6. A ball is thrown vertically up at 30 m/s from the ground. Taking g = 10 m/s², the time for which it stays above a height of 25 m is:
Q7. A projectile is launched at 50 m/s at an angle of 53° above the horizontal. Taking sin 53° = 0.8, cos 53° = 0.6 and g = 10 m/s², its horizontal range is:
Q8. A ball rolls off the edge of a 1.25 m high table with horizontal speed 3 m/s. Taking g = 10 m/s², it lands at a horizontal distance of:
Q9. A projectile is fired at 40 m/s at 60° above the horizontal. Its speed at the highest point of its path is:
Q10. A boat that moves at 5 m/s in still water must cross a river 200 m wide flowing at 3 m/s, travelling along the shortest path (straight across). The time taken is:
Q11. Rain falls vertically at 8 m/s. A man walks on a level road at 6 m/s. The speed of the rain relative to him is:
Q12. Masses of 3 kg and 5 kg hang over a light frictionless pulley in an Atwood machine. Taking g = 10 m/s², the tension in the string is:
Q13. A block slides down an incline of 37° with coefficient of kinetic friction 0.25. Taking sin 37° = 0.6, cos 37° = 0.8 and g = 10 m/s², its acceleration is:
Q14. A 60 kg student stands on a spring scale in a lift. The scale reads 540 N. Taking g = 10 m/s², the acceleration of the lift is:
Q15. A 20 g bullet moving at 300 m/s horizontally embeds in a 1.98 kg block resting on a frictionless surface. The speed of the block with the bullet is:
Q16. A 4 kg gun fires a 25 g bullet at 400 m/s. The recoil speed of the gun (ignoring the bullet's mass in the gun's total) is:
Q17. A 0.2 kg ball strikes a wall at 15 m/s and rebounds along the same line at 10 m/s. If the contact lasts 0.01 s, the average force on the ball is:
Q18. A 2 kg block moving at 6 m/s collides head-on and elastically with a stationary 4 kg block. The speed of the 4 kg block afterwards is:
Q19. A 3 kg body moving at 4 m/s collides with a stationary 1 kg body and they stick together. The kinetic energy lost is:
Q20. A ball dropped from 1.8 m rebounds from the floor to a height of 0.8 m. The coefficient of restitution is:
Q21. A 5 kg block on a rough horizontal floor (μₖ = 0.4) is pulled by a horizontal 30 N force. Taking g = 10 m/s², its acceleration is:
Q22. A car travelling at 20 m/s locks its wheels on a level road where μ = 0.5. Taking g = 10 m/s², it skids to rest in:
Q23. Blocks of 2 kg and 3 kg lie on a frictionless table, joined by a light string. A horizontal 10 N force pulls the 3 kg block directly away from the 2 kg block. The tension in the string is:
Q24. A rocket's engine produces a thrust of 6000 N with an exhaust speed of 2000 m/s relative to the rocket. The mass of gas expelled per second is:
Q25. A heavy truck collides head-on with a small car. Compared with the force the truck exerts on the car, the force the car exerts on the truck during the collision is:
Q26. A stone is dropped from rest from a tall tower. Taking g = 10 m/s², the distance it falls during the third second is:
Q27. A car travels the first half of a journey's distance at 60 km/h and the second half at 40 km/h. Its average speed for the whole journey is:
Q28. Car A at 20 m/s follows car B, which moves in the same direction at 15 m/s and is 100 m ahead. Car A catches up with car B after:
Q29. The linear momentum of a body is increased by 10% while its mass stays constant. The percentage increase in its kinetic energy is:
Q30. A cart moving to the left at 6 m/s is brought to rest and then driven to the right at 6 m/s, the whole change taking 3 s at uniform acceleration. Taking right as positive, its acceleration is: