Answer:
The net friction force is 8.01 N
Explanation:
Net friction force = mass of hockey puck × acceleration
From the equations of motion
v^2 = u^2 + 2as
v = 40 m/s
u = 0 m/s (puck was initially at rest)
s = 30 m
40^2 = 0^2 + 2×a×30
60a = 1600
a = 1600/60 = 26.7 m/s^2
The acceleration of the puck is 26.7 m/s^2
Net friction force = 0.3 × 26.7 = 8.01 N
Explanation:
It is given that,
Diameter of the semicircle, d = 45 m
Radius of the semicircle, r = 22.5 m
Speed of greyhound, v = 15 m/s
The greyhound is moving under the action of centripetal acceleration. Its formula is given by :
We know that, 
Hence, this is the required solution.
Answer:
Explanation:
The magnetic field strenght on the z-axis at a distance d from the center is,
Our values are:
Replacing,
Answer:
178.75 N
Explanation:
The force necessary to start moving the crate must be equal to or more than the frictional force (resistive force) acting on the crate but moving in an opposite direction to the frictional force.
So, we find the frictional force, Fr:
Fr = -μmg
Where μ = coefficient of friction
m = mass
g = acceleration due to gravity
The frictional force is negative because it acts against the direction of motion of the crate.
Fr = -0.57 * 32 * 9.8
Fr = - 178.75 N
Hence, the force necessary to move the crate must be at least equal to but opposite in direction to this frictional force.
Therefore, this force is 178.75 N
Answer:
Hysteresis, Eddy current, flux leakage and resistance of winding are those four reasons. It is impossible to overcome this four reasons, Hence transformer never be 100% efficient.
