Q1. In a single movable pulley system, if the load is 400 N, what is the ideal effort required to lift it?A 200 N B 400 N C 800 N D 100 N View full solution →
Q2. A worker pulls a block along a horizontal surface with a constant force of 50 N, covering a distance of 10 m. If the force of friction acting on the block is 10 N, what is the net work done on the block?A 100 J B 400 J C 600 J D 500 J View full solution →
Q3. A boy running at 4 m/s has a kinetic energy of 40 J. If he doubles his speed, what will be his new kinetic energy?A 160 J B 80 J C 10 J D 20 J View full solution →
Q4. A 100 W bulb is left on for 10 hours. If electricity costs Rs. 5 per unit (1 unit = 1 kWh), what is the cost of using the bulb?A Rs. 1.00 B Re. 0.50 C Rs. 5.00 D Rs. 10.00 View full solution →
Q5. Why is the efficiency of a real machine always less than its ideal mechanical advantage divided by its velocity ratio?A Because velocity ratio is always greater than mechanical advantage. B Because of the principle of conservation of energy. C Because of energy losses, primarily due to friction. D Because the load is always less than the effort. View full solution →
Q6. Which of the following activities involves negative work done by a force?A A braking force bringing a car to a stop. B A satellite orbiting Earth. C Lifting a book from a table. D A car accelerating on a straight road. View full solution →
Q7. Two identical cars, A and B, are moving such that car A has twice the speed of car B. What is the ratio of their kinetic energies (KE_A : KE_B)?A 2:1 B 1:4 C 1:2 D 4:1 View full solution →
Q8. A 10 kg object is lifted to a height of 5 meters. Calculate the work done against gravity. (Take g = 10 m/s²)A 50 J B 100 J C 1000 J D 500 J View full solution →
Q9. A spring is compressed by a distance 'x'. If the compression is doubled to '2x', how does the elastic potential energy stored in the spring change?A It remains the same. B It doubles. C It halves. D It quadruples. View full solution →
Q10. A 2 kg mass is attached to a spring with a spring constant k. It is pulled by 0.1 m and released. What type of energy is stored in the spring when it is pulled?A Elastic potential energy B Gravitational potential energy C Chemical energy D Kinetic energy View full solution →
Q11. If a 100 N force is applied to move a box 5 m horizontally, but the angle between the force and displacement is 60 degrees, calculate the work done.A 0 J B 500 J C 250 J D 433 J View full solution →
Q12. Assertion: The work done by a force can be zero even if the force and displacement are non-zero. Reason: Work done is a scalar quantity and depends on the angle between force and displacement.A Both Assertion and Reason are true but Reason is not the correct explanation of Assertion. B Both Assertion and Reason are true and Reason is the correct explanation of Assertion. C Assertion is false but Reason is true. D Assertion is true but Reason is false. View full solution →
Q13. A motor raises a 500 kg load through a vertical height of 10 m in 20 seconds. Calculate the power of the motor. (Take g = 10 m/s²)A 5000 W B 250 W C 10000 W D 2500 W View full solution →
Q14. A ball is thrown vertically upwards. What happens to its kinetic energy and potential energy as it rises to its maximum height?A Both kinetic energy and potential energy increase. B Kinetic energy increases, potential energy decreases. C Kinetic energy decreases, potential energy increases. D Both kinetic energy and potential energy decrease. View full solution →
Q15. A loaded truck requires less effort to push up a longer, less steep ramp than a shorter, steeper ramp to reach the same height. Which simple machine principle is at play here?A Wheel and Axle B Inclined Plane C Pulley D Lever View full solution →
Q16. A machine has a mechanical advantage of 4 and a velocity ratio of 5. What is the efficiency of the machine?A 125% B 80% C 40% D 20% View full solution →
Q17. A man carries a load of 20 kg on his head and walks 100 m on a horizontal road. The work done by the man against gravity is:A 20000 J B 200 J C 0 J D 2000 J View full solution →
Q18. If a human heart pumps 70 mL of blood in one beat against a pressure of 120 mmHg (equivalent to 16000 Pa) and beats 72 times per minute, calculate the power of the heart. (1 mL = 10^-6 m³)A 0.134 W B 13.4 W C 1.34 W D 0.0134 W View full solution →
Q19. Which type of lever always has a mechanical advantage greater than 1?A Class III lever B Class II lever C All types of levers D Class I lever View full solution →
Q20. An object of mass 'm' is dropped from a height 'H'. What is its total mechanical energy just before it hits the ground, assuming no air resistance?A mgh B 1/2 mv² (where v is impact velocity) C Both B and C are correct and equal to the initial potential energy. D 0 View full solution →