Physics Past Questions and Answers

A machine has an efficiency of 60%. If the machine is required to overcome a load of 30 N with a force of 20 N calculate its mechanical advantage?

A body weighing 10 N in air is partially immersed in water. It displaces water of mass 0.3 kg. What is the upthrust on the body? (g = 10 ms^-2)

A mercury-in-glass thermometer reads - 20^o at the ice point and 100^o at the steam point. Calculate the celcius temperature corresponding to 70^o on the thermometer.

A brass rod is 2 m long at a certain temperature. Calculate the linear expansion of the rod for a temperature change of 100K. (Take the linear expansivity of brass as 1.8 x 10'5K").

A body of specific heat capacity 450J kg^-1 K^-1 falls to the ground from rest through a vertical height of 20m. Assuming conservation of energy, calculate the change in temperature of the body on striking the ground level. (g = 10ms^-2)