59. A block resting at the top of a plane inclined at 26° with the horizontal slides down with an acceleration
of 1.96 m/s^2 [down the plane). Calculate the coefficient of
kinetic friction.

μ = 0.265

Explanation:

F = ma

mgsinθ - μmgcosθ = ma

gsinθ - μgcosθ = a

gsinθ - a = μgcosθ

μ = (gsinθ - a) / gcosθ

μ = (9.81sin26 - 1.96) / 9.81cos26

μ = 0.265439...

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000