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 m/s. How long does the body take to stop?
Answer» Given F = – 50 N (retarding force) m = 20 kg u = 15 m/s. V = 0 m/s t = ? F = ma ⇒ a = \(\frac {F}{m} =\frac {-50}{20}\) = – 2.5m/s² but we know that V = u + at 0 = 15 + (- 2.5) t ⇒ t = 6 s.

A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of 15 m/s. How long does the body take to stop?

Answer»

Given F = – 50 N (retarding force)

m = 20 kg

u = 15 m/s. V = 0 m/s

t = ?

F = ma

⇒ a = \(\frac {F}{m} =\frac {-50}{20}\)

= – 2.5m/s²

but we know that

V = u + at

0 = 15 + (- 2.5) t

⇒ t = 6 s.