1)
Frictional force on the body = μ m g = 1 * 5 kg * g = 5 g N
Net force acting on the body = 50 N - friction force = 50 N - 5 g
If g = 10 m/s², then net force = 50 - 50 N = 0. So acceleration is 0. Velocity = 0.
The body stays at rest.
If g = 9.81 m/s² then net force = 50 - 5 * 9.8 = 1 N
acceleration = net force / mass = 1 / 5 = 0.2 m/sec²
Distance traveled in 3 seconds is S = u t + 1/2 a t² = 0 + 1/2 * 0.2 * 3² = 0.9 meters
2)
Net force = mass * acceleration = 100N/ g * 1 m/s² = F - μ (m g) = F - μ 100 N
μ = [ F - 100 / g ] / 100
If g = 10 m/s², μ = (F - 10)/100
If g = 9.81 m/s², μ = ( F - 10.19)/100
3)
m A = net force = Force applied F - friction μ m g
A = (F - μ m g)/m = F/m - μ g --- equation 1
acceleration increases by 2 units, if μ is reduced to 1/3μ.
A + 2 = F/m - (μ/3) g --- equation 2
( F/m - μ g) + 2 = F/m - μ g /3
2 μ g /3 = 2
μ = 3/g = 0.3 if g =10m/s² or 0.306, if g = 9.81 m/s²
