1. A body of mass 5 kg is taken
from a height 5m to 10m. Find the increase in its potential energy(g=10m/sec2)
2. How fast should a man of
mass 60 kg run so that his kinetic energy is 750 J?
3. A truck weighing 5 * 103
kgf and a cart weighing 500 kgf are moving with the same speed. Compare their
Kinetic energies?
4. A ball of mass 10 g falls
from a height of 5m. It rebounds from the ground to 4m. Find
a. The initial potential energy
of the ball
b. The K.E of the ball just
before striking the ground
c. The K.E of the ball after
striking the ground
d. The loss in K.E on striking
the ball
5. A spring is compressed in a
toy cart of mass 150 g. On releasing the cart, it moves with a speed of 0.2
m/sec. Calculate the potential energy of the spring
6. A two gear system has one wheel
with 50 teeth and the other wheel with 5 teeth. Find the gain in speed and gain
in torque which can be obtained by their combinations. What is gear ration in
each case?
7. A gear system has the
driving wheel of radius 18 cm and 100 teeth. It rotates at a speed of 30 rpm.
If the speed of the rotation of the driven wheel is 150 rpm, find : i) the gear
ratio ii) the no of teeth of the driven
wheel iii) the radius of the driven
wheel.
8. Draw a diagram showing the
combination of a movable pulley P1 with a fixed pulley P2 used for lifting up a
load W. a) State the function of the fixed pulley P2. b) If the free end of the string moves
through a distance x, by what distance is the load W raised ? c) What effort has to be applied to C to just
raise the load W= 20 kgf?
9. A block and tackle system
has two pulley in each block, with the tackle tied to the hook of the lower
block and the effort being applied upwards. a)
Draw a neat diagram to show this arrangement and calculate its mechanical
advantage b) If the load moves x
distance, by what distance will the free end of the string moves
10. A pulley system with a velocity ratio of 4 is
used to lift a load of 150 kgf through a vertical height of 20 m. The effort
required is 50kgf in the downward direction. Calculate: a) the distance moved by the effort b) the work done by the effort c)
the mechanical advantage d) the
efficiency of the pulley system e) the
total number of pulleys and the number of pulleys in each block (take g=10)
Heat
1. An iron ball requires 5000 j
heat energy to raise its temperature by 10 degree celcius. Calculate the heat
capacity of the iron ball
2. A body of mass 500g requires
3000 J of heat energy in order to raise its temperature from 35oC to
45 oC . Calculate the specific heat capacity of the body.
3. 40 g of water at 60 oC is poured into a vessel containing 50 kg of
water at 20 oC. The final temperature of the mixture is 30 oC
. Taking the specific heat of water as 4.2Jg-1K-1.
Calculate the thermal capacity of the vessel.
4. How much heat energy is required
to melt 5 kg of ice? Specific heat of ice is 336 Jg-1
