Answer:
a)15 N
b)12.6 N
Explanation:
Given that
Weight of block (wt)= 21 N
μs = 0.80 and μk = 0.60
We know that
Maximum value of static friction given as
Frs = μs m g = μs .wt
by putting the values
Frs= 0.8 x 21 = 16.8 N
Value of kinetic friction
Frk= μk m g = μk .wt
By putting the values
Frk= 0.6 x 21 = 12.6 N
a)
When T = 15 N
Static friction Frs= 16.8 N
Here the value of static friction is more than tension T .It means that block will not move and the value of friction force will be equal to the tension force.
Friction force = 15 N
b)
When T= 35 N
Here value of tension force is more than maximum value of static friction that is why block will move .We know that when body is in motion then kinetic friction will act on the body.so the value of friction force in this case will be 12.6 N
Friction force = 12.6 N
ANSWER
A convex lens acts a lot like a concave mirror. ... A concave lens acts a lot like a convex mirror. Both diverge parallel rays away from a focal point, have negative focal lengths, and form only virtual, smaller images.
Answer
Assuming the mass of the car, m = 43000 kg
initial speed u = 0
vertical distance moved, h = 8.8 m
spring constant k = 5 x 10⁵ N / m
acceleration of gravity = 9.8 m/s²
From law of conservation of energy ,
Gravitational potential energy at starting position =potential energy of the spring at maximum compression
x = 14.83 m
If the mass of the car is equal to 43000 Kg the spring is compressed to 14.83 m
