physics

The design of the thermostat of an electric iron is based on the?

A. emission of electrons from metals when heated B. increase in size of metals when heated C. increase in the…

6 years ago

An object of mass 0.25kg moves at a height h above the ground with a speed of 4ms-1, if its mechanical energy at this height is 12 J, determine the value of h. [g = 10ms-1]

A. 0.8m B. 4.0m C. 4.8m D. 5.6m Correct Answer: Option C C. 4.8m Explanation h = PE/mg−12/(0.25×10) = 4.8m

6 years ago

Which of the following devices convert heat energy to electrical energy?

A. transformer B. dynamo C. thermocouple D. thermostat Correct Answer: Option C C. thermocouple

6 years ago

A ball is dropped and it hits the floor at a point A. It rebounds upward to a point B. While moving from A to B its?

A. kinetic energy is increasing B. potential energy is increasing C. potential energy is decreasing D. kinetic energy remains constant…

6 years ago

An object of mass 2kg moving with a velocity 3ms‾¹ collides head-on with another object of mass 1kg moving in the opposite direction with a velocity of 4ms‾¹. If the objects stick together after collision, calculate their common speed.

A. 0.60ms‾¹ B. 0.67ms‾¹ C. 2.00ms‾¹ D. 3.33ms‾¹ Correct Answer: Option B B. 0.67ms‾¹ Explanation M1V1−(M2V2)=V(M1+M2) 2 x 3 -…

6 years ago

The mass attached to a string is moving in a circular path. If the speed is doubled, the tension in the string will be?

A. doubled B. halved C. four times as great D. one-fourth as much Correct Answer: Option C C. four times…

6 years ago

The diagram above illustrates a bar magnet near a coil connected to a galvanometer, When the magnet is rapidly moving towards the coil. Which of the statements above is/are correct?

i. e.m.f. is induced in the coil ii. the galvanometer needle deflects iii. the magnet is attracted by the coil.…

6 years ago

The diagram below represents the displacement-time graph of the motion of an object thrown upwards. The velocity of the object at point P is?

A. maximum B. uniform C. zero D. terminal Correct Answer: Option C

6 years ago

A rectangular block of dimensions 2.0m x 1.0m x 0.5m weighs 200N. calculate the maximum pressure exerted by the block on a horizontal floor.

A. 100Nm‾² B. 200Nm‾² C. 300Nm‾² D. 400Nm‾² Correct Answer: Option A A. 100Nm‾² Explanation P = wt/A=200/(2×1)=100Nm‾²

6 years ago

A car traveling with a uniform velocity of 30ms-1 along a horizontal road overcomes a constant frictional force of 600N. Calculate the power of the engine of the car?

A. 18kW B. 20kW C. 180kW D. 200kW Correct Answer: Option A A. 18kW Explanation P = FV = 600…

6 years ago
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