Answer:
Explanation:
Given:
<u>So, the energy dissipated during the skidding of car:</u>
<em>Frictional force:</em>
where N = normal reaction by ground on the car
<em>Now from the work-energy equivalence:</em>
is the dissipated energy.
Mass of the block = 1.4 kg
Weight of the block = mg = 1.4 × 9.8 = 13.72 N
Normal force from the surface (N) = 13.72 N
Acceleration = 1.25 m/s^2
Let the coefficient of kinetic friction be μ
Friction force = μN
F(net) = ma
μmg = ma
μg = a
μ =
μ =
μ = 0.1275
Hence, the coefficient of kinetic friction is: μ = 0.1275
Explanation:
According to Newton's second law of motion, the rate of change of momentum is directly proportional to the applied unbalanced force. The mathematical expression is given by:
Where
F is the applied force
m is the mass of the object
v is the velocity with which it is moving
Momentum of a particle is given by the product of mass and velocity as :
Hence, this is the required solution.
Answer:
The farther star will appear 4 times fainter than the star that is near to the observer.
Explanation:
Since it is given that the luminosity of the 2 stars is same thus they radiate the same energy per unit time
Consider a spherical wave front of energy 'E' that leaves both the stars (Both radiate 'E' as they have same luminosity)
This Energy is spread over the whole surface area of sphere Thus when the wave front is at a distance 'r' the energy per unit surface area is given by
For the star that is twice away from the earth the distance is '2r' thus we will receive an energy given by
Hence we sense it as 4 times fainter than the nearer star.