Physics
A block and tackle has two pulleys 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 up by a distance x, by what distance will the free end of the string move up?
Related Questions
State whether work is done or not by writing yes or no, in the following cases?
(a) A man pushes a wall.
(b) A coolie stands with a box on his head for 15 min.
(c) A boy climbs up 20 stairs.
The diagram given below shows a ski jump. A skier weighing 60kgf stands at A at the top of ski jump. He moves from A and takes off for his jump at B.
(a) Calculate the change in the gravitational potential energy of the skier between A and B.
(b) If 75% of the energy in part (a) becomes the kinetic energy at B, calculate the speed at which the skier arrives at B.
(Take g = 10 ms-2).
(c) Does total mechanical energy change during the ski jump?
A person standing between two vertical cliffs and 640 m away from the nearest cliff produces a sound. He hears the first echo after 4 s and the second echo 3 s later. Calculate :
(a) The speed of sound in air and
(b) The distance between the cliffs
Two pendulums C and D are suspended from a wire as shown in the given figure. Pendulum C is made to oscillate by displacing it from it's mean position. It is seen that D also starts oscillating.
(i) Name the type of oscillation, C will execute.
(ii) Name the type of oscillation, D will execute.
(iii) If the length of D is made equal to C, then what difference will you notice in the oscillations of D?
(iv) What is the name of the phenomenon when the length of D is made equal to C?