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(10 points) A ino kg mootball prayer does a chin up bypulling nimisen up by mis

ID: 1627257 • Letter: #

Question

(10 points) A ino kg mootball prayer does a chin up bypulling nimisen up by mis arms an adan monial height of 50.0 cm above the floor. If he does a total of 25 chin-ups, how much work does he do? (10 points) A 2.00 kg block is placed at the position A on the track that is 3.00 m above the ground as in Fig 1. Paths A-B and C-D of the track are frictionless, while section B-C is rough with a coefficient of kinetic friction of 0.350 and a length of 1.50 m. Find (a) the total energy of the block at A, (b) the velocity of the block at B, (c) the energy lost along path B-C, and (d) how high the block rises along path C-D

Explanation / Answer

M=2kg h=3m

Acc to conservation of energy mgh=1/2mv^2

So v =(2gh)^1/2

V=7.7m/s velocity at B

Total energy atA =mgh=2×3×9.8=58.8J

Energy lost along path BC= force of friction ×distance travelled =u×m×g×BC=0.35×2×9.8×1.5=10.3J

Energy remaining 58.8-10.3=48.51J

Again apply law of conservation of energy

mgh=48.51

h=2.47m