Question

A block rests on a horizontal frictionless surface. A string is attached to the block, and is pulled with a force of 59.0 N at an angle o above the horizontal. After the block is pulled through a distance of 1.70 m, its speed is 2.60 m/s, and 44.0 ) of work has been done on it. What is the angle e? Submit Answer Tries 0/8 Calculate the mass of the block. Submit Answer Tries 0/8 This discussion is closed. Send Feedback

Answer 1

given

force is 59 N

S = 1.7 m

the final velocity is V = 2.6 m/sec

W = 44 J

a )

the horizontal force F_h = 59 cos$\theta$

W = F_h.S

44 = 59 cos$\theta$ x 1.7

cos$\theta$ = 44 / 59 x 1.7

the angle is $\theta$ = 63.98^o  

b )

here initial velocity is zero

so u = 0

using kinematic equation

V² = u² + 2 a S

2.6² = 0 + 2 x a x 1.7

a = 2.6² / 2 x 1.7

a = 1.988 m/sec²

according to Newton's second law

F = m a

59 cos$\theta$ = m x 1.988

59 cos63.98 = m x 1.988

m = 59 cos63.98 / 1.988

so the mass of the block is m = 13.0193 kg