Answer to Question #104292 in Classical Mechanics for Marcus

Question

1. A bicycle is travelling at constant velocity on a horizontal road. Which of the following statements are true? (You may choose more than one.)
a) The total force on the bicycle is parallel to the motion.
b) The total force on the bicycle is anti parallel to the motion.
c) No forces are acting on the bicycle.
d) Various forces are acting on the bicycle, and their sum is zero.
e) Air resistance forces are approximately parallel to the velocity.
f) Air resistance forces are approximately anti parallel to the velocity.
g) Overall, friction between the tires and the road is pushing the bicycle forwards.

2. A slack rope walker balances on a rope tied between two trees. For a short time, he is not moving. His mass is 72 kg. The rope makes an angle theta = 22 degrees with the horizontal on either side. What is the magnitude of the tension in the rope?

Answer 1

1) Answer:

d) Various forces are acting on the bicycle, and their sum is zero.

f) Air resistance forces are approximately anti parallel to the velocity.

g) Overall, friction between the tires and the road is pushing the bicycle forwards. 

2) For the equilibrium:

$$mg=2T\sin{22}$$

$$(72)(9.8)=2T\sin{22}$$

$$T=942\ N$$