4- A skier of mass 67 kg is pulled up a slope by a motor-driven cable. a) What p
ID: 1607193 • Letter: 4
Question
4- A skier of mass 67 kg is pulled up a slope by a motor-driven cable.
a) What power (expressed in hp) must a motor have to perform this task?
3-A 0.24-kg stone is held 1.5 m above the top edge of a water well and then dropped into it. The well has a depth of 5.2 m.
(a) Taking y = 0 at the top edge of the well, what is the gravitational potential energy of the stone–Earth system when it reaches the bottom of the well?
(c) What is the change in gravitational potential energy of the system from release to reaching the bottom of the well?
2-A 69-kg base runner begins his slide into second base when he is moving at a speed of 4.2 m/s. The coefficient of friction between his clothes and Earth is 0.70. He slides so that his speed is zero just as he reaches the base.
b) How far does he slide??
1-In 1990 Walter Arfeuille of Belgium lifted a 281.5-kg object through a distance of 17.1 cm using only his teeth.
(a) How much work did Arfeuille do on the object?
J
(b) What magnitude force did he exert on the object during the lift, assuming the force was constant?
Explanation / Answer
4- Inufficient information
5:
(a) PE = m g h = 0.24 x 9.8 x (1.5 + 5.2) = 18.35 J
(B) change in PE = PEf - PEi = 0 - 18.35 J = - 18.35 J
6: a = - uk g = 0.70 x 9.8 = - 6.86 m/s^2
vi = 4.2 m/s
vf = 0
Applying vf^2 - vi^2 =2 ad
0^2 - 4.2^2 = 2(-6.86)(d)
d = 1.29 m
7. Work done = F.d = m g d
= 281.5 x 9.8 x 0.171
= 471.74 J ]
(B) F = m g = 281.5 x 9.8 = 2758.7 J
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.