Advertisements
Advertisements
प्रश्न
A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. If the value of g be 10 m/s2, the work done by the girl against the gravitational force will be :
पर्याय
6000 J
0.6 J
0 J
6 J
उत्तर
The girl is moving with the bag on a levelled road. Her direction of motion is perpendicular to the direction of gravitational force. So, work done by the girl against gravity is zero. Therefore, the answer is 0 J
(c) 0 J
APPEARS IN
संबंधित प्रश्न
Name a common device where a gear train is used
No work is done by a force if the body
What is the condition for a force to do work on a body?
What are the units of (a) work, and (b) energy?
A person of mass 50 kg climbs a tower of height 72 metres. Calculate the work done. (g = 9.8 m s−2).
How much work is done when a force of 2 N moves a body through a distance of 10 cm in the direction of force?
Ravi applied a force of 10 N and moved a book 30 cm in the direction of the force. How much was the work done by Ravi?
Give an example
Chemical energy changes to heat energy.
Give an example
Light energy changes to electrical energy.
A canon ball of mass 500g is fired with a speed of 15m/s-1. Find: its momentum.
In the following case write yes, if the work is being done and no if no work is being done.
A boy climbing up a staircase.
(i) A 200g ball is thrown vertically upward with an initial velocity of 30 ms-1. Draw a velocity-time graph for the motion of ball.
(ii) How long will the ball take to reach the highest point?
(iii) What will be the kinetic energy of ball, when it returns to the starting point, neglecting the air resistance?
(iv) What will be the potential energy of ball at highest point?
Who is the odd one out?
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A donkey is carrying a load on its back.