A mechanic is trying to loosen a tight bolt using a wrench. To make the task easier, he holds the wrench at its farthest end and applies force perpendicular to the handle. Why does this method help in loosening the bolt?
The moment of force increases due to a larger perpendicular distance.
The force applied decreases, making it easier to turn the bolt.
The wrench becomes lighter, reducing the effort needed to rotate the bolt.
The force applied gets distributed evenly along the wrench, reducing effort.
A tightrope walker carries a long pole while walking on the rope. How does the pole help them maintain balance?
It shifts their center of gravity higher, making balancing easier.
It makes them lighter, reducing the risk of falling.
It lowers their center of gravity and increases stability.
It reduces friction between their feet and the rope, allowing smoother movement.
A person pushes a shopping cart with a force of 50 N at an angle of 60° while waiting in line. The cart does not move. What is the work done by the applied force?
100 J
50 J
25 J
0 J
Question 4
4.
Hydrogen-powered fuel cell vehicles generate electricity to run the motor by reacting hydrogen and oxygen. Which of the following best describes the energy conversion process?
Thermal → Mechanical → Electrical
Chemical → Electrical → Mechanical
Kinetic → Chemical → Mechanical
Electrical → Chemical → Thermal
A company claims to have designed a perpetual motion machine that can run indefinitely without an external energy source while performing useful work. Why is this claim false?
It violates the law of conservation of momentum.
It only works in zero gravity, which is not practical on Earth.
It violates the law of conservation of energy.
It relies on chemical energy, which will eventually run out.
A crane lifts a 500 kg load vertically upwards by 20 m in 10 seconds at a constant speed. What is the power output of the crane? (Take g = 10 m/s²)
10000 W
100000 W
1000 W
100 W
A truck and a car are moving on a highway with the same momentum. However, the truck has more mass than the car. Which of the following statements is true about their kinetic energies?
The car has more kinetic energy because it has less mass.
The truck has more kinetic energy because it has more mass.
Both have the same kinetic energy since their momenta are equal.
The kinetic energy depends only on speed, so it cannot be determined from the given information.
A car is moving with constant speed on a circular track. Which of the following statements is correct?
The car experiences an outward force due to inertia, which keeps it moving in a circular path.
Friction acts as a centrifugal force.
The acceleration of the car is zero because the speed remains constant.
The velocity of the car changes at each point.
A 40 kg child sits 2 m from the pivot of a seesaw. On the other side, at a distance of 3 m from the pivot, an adult sits to balance the seesaw. What should be the minimum mass of the adult to keep the seesaw in equilibrium?
24.5
25.6
26.7
27.8
If the mass of an object is doubled, keeping the height same, its gravitational potential energy will:
Remain the same
Double
Become half
Become four times
If an object moves with constant velocity, what can be said about the net work done on it?
Positive
Negative
Equal to the mass of the object
Zero
A shopkeeper turns a key in a lock to close the shutter. If the key is rotated clockwise, the moment of force is:
Positive
Negative
Infinity
Zero
A moving car has kinetic energy. What happens to this energy when the car stops due to brakes?
It converts into heat energy
It converts into potential energy
It remains stored in the car
It disappears
Two workers push identical carts with the same force for the same distance. Worker X does it in 5 seconds, and Worker Y does it in 10 seconds. Which statement is correct?
Worker Y has more power than Worker X.
Worker Y did more work than Worker X.
Worker X and Worker Y have equal power.
Worker X has more power than Worker Y.
How many joules are there in 2 kilowatt hour (kWh)?
7,200 J
72,000 J
7,200,000 J
7,200,000,000 J
Which of the following objects can have a center of gravity outside its physical material?
A thin ring
A solid cone
A uniform bar
A sphere
Assertion (A): Energy can be transferred from one form to another.
Reason (R): Energy is always conserved, and it cannot be created or destroyed.
Both assertion and reason are true, and reason is the correct explanation for assertion.
Both assertion and reason are true, but reason is not the correct explanation for assertion.
Assertion is true, but reason is false.
Assertion is false, but reason is true.
A parachutist descending at a constant velocity experiences:
Unstable equilibrium
Neutral equilibrium
Static equilibrium
Dynamic equilibrium
Which of these tools works based on the principle of a couple?
Hammer
Pulley
Spanner
Ramp
While taking a sharp turn on a bike, a rider leans inward toward the curve. What is the reason for this action?
To increase the centripetal force by moving away from the center of the curve.
To reduce the effect of centripetal force, which pushes the rider outward.
To balance the centrifugal force acting outward with the centripetal force.
To increase the centrifugal force so that the bike moves faster around the curve.
