The world record for pole vaulting is 6.15 m. If the pole vaulter’s gravitational potential is 4942 J, what is his mass?
1 answer:
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Answer:
Work done, W = 6 J
Explanation:
It is given that,
Force of gravity acting on the book, weight of the book is 15 N
We need to find the work done in lifting the book straight up for a distance of 0.4 meters.
The weight of the book is acting in downward direction and the book is lifted straight up, it means angle between them is 180 degrees. Work done is given by :
So, the magnitude of work done in lifting the book is 6 joules.
Complete Question:
The elastic energy stored in your tendons can contribute up to 35 % of your energy needs when running. Sports scientists have studied the change in length of the knee extensor tendon in sprinters and nonathletes. They find (on average) that the sprinters' tendons stretch 43 mm , while nonathletes' stretch only 32 mm . The spring constant for the tendon is the same for both groups, . What is the difference in maximum stored energy between the sprinters and the nonathlethes?
Answer:
Explanation:
Sprinters' tendons stretch,
Non athletes' stretch,
Spring constant for the two groups, k = 31 N/mm = 3100 N/m
Maximum Energy stored in the sprinter,
Maximum energy stored in the non athletes,
Difference in maximum stored energy between the sprinters and the non-athlethes: