Answer:
Explanation:
Given
car A had a head start of 
and it starts at x=0 and t=0
Car B has to travel a distance of 
where 
is the distance travel by car A in time t
distance travel by car A is
For car B with speed 
If the motorcycle can go from 0 to 50mph in 3 seconds the person is describing the motorcycle's acceleration.
Answer: B. Concrete
Explanation:
Let N = reacting force pressing the bodies in context together (units in Newtons),
The question stated that the force pressing the two mounted/stacked objects together is equal to the weight of the object on top.
We need to start by finding the weight of the piece of wood.
friction is given by
f = μN
The value of f is 22.5,
and from the chart reference the coefficient of friction between wood and stone, μ is 0.30.
22.5 = 75. 0.30
Putting the values into the equation: 22.5 = 0.30N.
Divide both sides by 0.30 to find the value of N:
N= 22.5/0.3 = 75
Now that the piece of wood will be placed on another surface, its weight of 75 Newton is the force pressing the two bodies together.
To determine the new surface, you should find the new coefficient of friction by using the new value of the force of friction given 46.5:
46.5 = µ(75).
Divide both sides by 75 to isolate μ.
The refer chart also indicates that the coefficient of friction equals 0.62 between wood and concrete, so the new surface corresponding to 0.62 is the concrete, which is (B).
Answer:
Explanation:
Let Torque due to friction be
F
Net torque
= 46 - F
Angular impulse = change in angular momentum
=( 46 - F ) x 17 = I X 580
When external torque is removed , only friction creates torque reducing its speed to zero in 120 s so
Angular impulse = change in angular momentum
F x 120 = I X 580
( 46 - F ) x 17 = F x 120
137 F = 46 x 17
F = 5.7 Nm
b )
Putting this value in first equation
5.7 x 120 = I x 580
I = 1.18 kg m²
