I would say your answer to this question would be D
Answer:
a) 
b) 
Explanation:
Given:
- mass of the body,

- mass of the tyre,

- length of hanging of tyre,

- distance run by the body,

- acceleration of the body,

(a)
Using the equation of motion :
..............................(1)
where:
v=final velocity of the body
u=initial velocity of the body
here, since the body starts from rest state:

putting the values in eq. (1)


Now, the momentum of the body just before the jump onto the tyre will be:



Now using the conservation on momentum, the momentum just before climbing on the tyre will be equal to the momentum just after climbing on it.



(b)
Now, from the case of a swinging pendulum we know that the kinetic energy which is maximum at the vertical position of the pendulum gets completely converted into the potential energy at the maximum height.
So,



above the normal hanging position.
11.46 meters
55 km/h = ? m/s
55 km/h × 1000 (meters per km) = 55,000 m/h
55,000 m/h ÷ 3,600 (seconds in an hour) = 15.28 m/s
15.28 m/s × 0.75 s = 11.46 m
Answer:
The elevator must be moving upward.
Explanation:
During the motion of an elevator, the weight of the person deviates from his or her actual weight. This temporary weight during the motion is referred to as "Apparent Weight". So, when the elevator is moving downward, the apparent weight of the person becomes less than his or her actual weight.
On the other hand, for the upward motion of the elevator, the apparent weight of the person becomes more than the actual weight of that person.
Since the apparent weight (645 N) of the student, in this case, is greater than the actual weight (615 N) of the student.
<u>Therefore, the elevator must be moving upward.</u>