A constant retarding force of 50 N is applied to a body of mass 20 kg

1.	A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of 15 ms-1. How long does the body take to stop?(a) 0.75 s (b) 1.33 s (c) 6 s (d) 35 s
Answer» Acceleration a = \(\frac{-F}{m}\) = \(\frac{50}{20}\) = -2.5 ms^-2 u = 15 ms^-1 V = 0 t = ? v = u + at 0 = 15 – 2.5t t = \(\frac{15}{2.5}\) =6s

A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of 15 ms-1. How long does the body take to stop?(a) 0.75 s (b) 1.33 s (c) 6 s (d) 35 s

Answer»

Acceleration a = \(\frac{-F}{m}\) = \(\frac{50}{20}\) = -2.5 ms^-2

u = 15 ms^-1

V = 0

t = ?

v = u + at

0 = 15 – 2.5t

t = \(\frac{15}{2.5}\) =6s