Physics Past Questions and Answers

A block and tackle system has 6 pulleys. If the efficiency of the machine is 60%, determine its mechanical advantages

A 12.0
B 10.0
C 3.6
D 1.8

Question 3052:

Which of the following actions will improve the efficiency of the pulley system?

A Reducing the mass of the pulley
B Increasing the friction force between the string and the pulley
C Increasing the mass per unit length of the string of the pulley
D Increasing the mass of the pulley

Question 3053:

The ice and steam points of a certain thermometer are -20^o and 100^o respectively. Calculate the Celsius temperature temperature corresponding to 70^o on the thermometer

A 84.0^o
B 75.0^o
C 64.0^o
D 58.0^o

Question 3054:

The silver coating on the inside of a vacuum flask reduces heat loss by

A Conduction
B Radiation
C Condensation
D Convention

Question 3055:

Water of mass 120g at 50^oC is added to 20og of water at 10^oC and the mixture is well stirred. Calculate the temperature of the mixture. [Neglect heat losses to the surrounding]

A 60^oC
B 40^oC
C 25^oC
D 10^oC