Physics Answers

A load at rest on the floor is subjected to a force making it move a certain distance. The work produce is 2000 J. The load was acted on by the force for 2 seconds. What is the amount of power?

A force of 500 N acts horizontally on a load at rest on the floor. The load moves a distance of 20 m in 10 s. What is the amount of power?

An airliner must reach a speed of 110m/s to take off. If the available runway is 2.4 km and the aircraft accelerates uniformly from rest at one end, what minimum acceleration must be available if it is to take off?

The length of the mercury column in a non-calibrated mercury thermometer is 5.5 cm

when its bulb is immersed in melting ice and 24.5 cm when the bulb is in the steam above

boiling water at sea level.

Determine the:

i. temperature for a length of 14 cm

ii. length for a temperature of 75 ℃

iii. length that would correspond to a temperature of – 6 ℃

A point of charge 10×10^-6C has a potential of 4×10^4V from a point 2mm from it. Calculate the potential due to the charge when the distance is now 16mm.

A copper rod whose length at 30m is 10.0m is heated to 50oc . Find its new length liner expansityfor copper as 0.00017k^-1

The wave length of a travelling wave is 5m at a frequency of 12Hz and has an amplitude of 15m, write down the equation of wave

What is the amount of heat required to change 2kg of ice at -15°c to water at 70°c ( C=4200jkg-¹k-¹

A. An airliner must reach a speed of 110 m/s to take off. If the available runway is 2.4 km

and the aircraft accelerates uniformly from rest at one end, what minimum acceleration

must be available if it is to take off?

B. A speeding motorist driving a car, passes a traffic police officer on a stationary

motorcycle. The police officer immediately gives chase: his uniform acceleration is

4ms-2

, and by the time he draws level with the speeding car, the police officer is

travelling at 30ms-1

.

i. How long did it take for the police officer to catch the car?

ii. If the speeding motorist continued to travel at a steady speed during the

chase, what was his speed?

C. A stone is thrown vertically upwards with a speed of 24.0 ms-1

. Using g = 9.8 ms-2

and

ignoring air resistance:

i. How much time is required to reach this height?

ii. Why are there two answers to (ii.)?

iii. Sketch the velocity-time graph for the stone, from it is released until it

returns to the thrower.