Work done in science is much different from the conception of work in our 1x
daily life. We consider that work is being done by a clerk while sitting at one
place from moming to evening. But in terms of physics, work is done only when
an applied force produces a displacement in the body in its own direction.
Work is a scalar quantity, but it can be negative, positive as well as zero.
(0) A continuous force of 60 N acting on a box continuously, displaces it by 10 m
in the direction of force. What is the work done?
(1) Write two conditions of zero work done.
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(ii) Give one example of a situation in which work done is negative.
(iv) Name the force which always does negative work on a body. Why does it do
only negative work?
(M) What is the work done by a satellite in going round the earth?
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The force acting on a body is capable of bringing changes in its motion 1कंटिन्यू स्पोर्ट ऑफ सिटी
Answers
Answer:
Explanation:
1. work done = force × displacement
w = 60×10=600j
2. Two conditions when the work done is zero are: (i) When there is no displacement (S=0) and, (ii) When the displacement is normal to the direction of the force
3. (i) When a body is thrown upwards, gravity does the negative work. Since the gravitational force acts downwards but the displacement is upwards. (ii) When we walk frictional force does the negative work since frictional force acts opposite to displacement.
4. Gravity
objective:
90 degrees
When a satellite moves around the Earth, then the force of gravity on the satellite is perpendicular to its displacement. Hence, the work done on the satellite by the Earth is zero.
positive, negative and zero
nection
true
false
ASSERTION AND REASON QUESTIONS
Both assertion and reason are false
Assertion is true, reason is false
. MULTIPLE CHOICE QUESTIONS:
c
He does zero work against force of gravity