Biker A is cruising at a speed of 10.0 m/s when she passes biker B who is at rest at the origin of the coordinate system. Biker
B immediately accelerates when he is passed, catching up with biker A after 1.00 minute.
(a) Draw graphs of position, velocity, and acceleration of both bikers as a function of time.
(b) What is the acceleration of biker B, assuming that it is constant?
(c) At what distance from the origin do the two bikers meet?
(d) What is the average speed of biker B during the first 30.0 seconds?
(a) Draw graphs of position, velocity, and acceleration of both bikers as a function of time.
(b) What is the acceleration of biker B, assuming that it is constant?
(c) At what distance from the origin do the two bikers meet?
(d) What is the average speed of biker B during the first 30.0 seconds?
1 answer:
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Answer:
a. 79.1 N
b. 344 J
c. 344 J
d. 0 J
e. 0 J
Explanation:
a. Since the crate has a constant velocity, its net force must be 0 according to Newton's 1st law. The push force by the worker must be equal to the friction force
on the crate, which is the product of friction coefficient μ and normal force N:
Let g = 9.81 m/s2
b. The work is done on the crate by this force is the product of its force and the distance traveled s = 4.35
c. The work is done on the crate by friction force is also the product of friction force and the distance traveled s = 4.35
This work is negative because the friction vector is in the opposite direction with the distance vector
d. As both the normal force and gravity are perpendicular to the distance vector, the work done by those forces is 0. In other words, these forces do not make any work.
e. The total work done on the crate would be sum of the work done by the pushing force and the work done by friction