The news media often report an earthquake's magnitude on the Richter scale. Which of the following items are characteristics of
1 answer:
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Answer:
- the speed of a person "stuck" to the wall is 14.8 m/s
- the normal force of the wall on a rider of m=54kg is 1851 N
- the minimum coefficient of friction needed between the wall and the person is 0.29
Explanation:
Given information:
the radius of the cylindrical room, R = 6.4 m
the room spin with frequency, ω = 22.1 rev/minutes = 22.1 = 2.31 rad/s
mass of rider, m = 54 kg
the speed of a person "stuck" to the wall
v = ω R
= 2.31 x 6.4
= 14.8 m/s
the normal force of the wall on a rider
F = m a
a = ω^2 R
= R
=
F =
=
= 1851 N
the minimum coefficient of friction needed between the wall and the person
F(friction) = μ N
W = μ N
m g = μ
g = μ
μ =
=
= 0.29
Answer:
Final Speed of Dwayne 'The Rock' Johnson = 15.812 m/s
Explanation:
Let's start out with finding the force acting downwards because of the mass of 'The Rock':
Dwayne 'The Rock' Johnson: 118kg x 9.81m/s = 1157.58 N
Now the problem also states that the kinetic friction of the desk in this problem is 370 N
Since the pulley is smooth, the weight of Dwayne Johnson being transferred fully, and pulls the desk with a force of 1157.58 N. The frictional force of the desk is resisting this motion by a force of 370 N. Subtracting both forces we get the resultant force on the desk to be: 1157.58 - 370 = 787.58 N
Now lets use F = ma to calculate for the acceleration of the desk:
787.58 = 63 x acceleration
acceleration = 12.501 m/s
Finally, we can use the motion equation:
here u = 0 m/s (since initial speed of the desk is 0)
a = 12.501 m/s
and s = 10 m
Solving this we get:
Since the desk and Mr. Dwayne Johnson are connected by a taught rope, they are travelling at the same speed. Thus, Dwayne also travels at 15.812 m/s when the desk reaches the window.