coefficient of static friction required between the sprinter's shoes and the track is u=0.293.
Explanation:-
The frictional coefficient is found from newton’s second law
We know that
Compare the Eqn (1) and eqn (2)
Mass (m) cancel each other both side
So
Coefficient of static friction
We know that
Kinetics
Substitute the value of acceleration in eqn (3)
So that
Coefficient of static friction.
Coefficient of static friction
Q₂ = 5833.33 J
Explanation:
First we need to find the energy supplied to the heat engine. The formula for the efficiency of the heat engine is given as:
η = W/Q₁
where,
η = efficiency of engine = 30% = 0.3
W = Work done by engine = 2500 J
Q₁ = Heat supplied to the engine = ?
Therefore,
0.3 = 2500 J/Q₁
Q₁ = 2500 J/0.3
Q₁ = 8333.33 J
Now, we find the heat discharged to lower temperature reservoir by using the formula of work:
W = Q₁ - Q₂
Q₂ = Q₁ - W
where,
Q₂ = Heat discharged to the lower temperature reservoir = ?
Therefore,
Q₂ = 8333.33 J - 2500 J
Q₂ = 5833.33 J