Question

A mysterious rocket-propelled object of mass 40.0kg is initially at rest in the middle of the horizontal, frictionless surface of an ice-covered lake, Then a force directed east and with magnitude F(t) = (15.GN/s )t is applied. How far does the object travel in the first 4.75s after the force is applied? Express your answer with the appropriate units.

Answer 1

apply force F = ma

so accleration a = F./m

a = 15.6/40

a = 0.39 m/s^2

now use the kinematic equation   S = 0.5 at^2

S = 0.5 * 0.39 * 4.75 *4.75

S = x = 4.4 m

Answer 2

a = F/m = 15.6t/40.0 =
a = 0.39 t

Velocity after time t1 = int(a*dt)

= 0.39/2 *t^2 = 0.195t^2

Distance covered = int(vdt)]t=0,4.75

= 0.195t^3 /3

= 6.966 m