Question

A). The breaks of a car of mass m = 2 103 Kg can provide a deaccelerating force of 104 N. How far will the car travel before coming to a complete stop if it moves initially at 10 m/s^-1?

B). A pendulum of mass 0.1 Kg hangs from the ceiling of car at rest. What would be its maximum angle with respect to the vertical axis if the car accelerates from rest to 5 ms-2. Take g=10 m/s^-2.

C). A disk rotates about its axis. At distance d=0.2 m from the center of this axis, an object is placed. When the disk rotates with an angular speed of greater than 50 rotations per minute, the object slides on the disk. Find the static friction coefficient between the object and the disk’s surface. Take g=10 ms^-2.

Thank you!

Answer 1

(1) ans

Accoding to the concept of the lwas of motion

force F=m(v^2-u^2)/2s

Given that

force F=104 N

mass m=2103 kg

initial velocityu=10 m/s

finial velocity v=0

now we find the displacement

displacement s=m(v^2-u^2)/2F

=2103(0^2-10^2)2*104

=1011.1 m

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(2) ans

According to the concept of the oscillation

Given that

mass m=0.1 kg

acceleration a=5 m/s^2

now we find the maximum angle

maximum angle =sin^-1(5/10)=30 degree

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According to the concept of the system of the paraticles

Given that

distance d=0.2 m

angular speed W=50 rotation/min=5.24 rad/s

now we find the static friction

coefficient of static friction =g/rw^2

=10/(0.2*5.24^2)

=1.82