Question

A constant horizontal force of 29.0 N is exerted by a string attached ot a 3.4 kg block being pulled across a table top. the block also experiences a frictional force of 7.0 N due to contact with the table.

A) what is the horizontal acceleration of the block?

B) If the block starts from rest, what will its velocity be after 2.5 seconds.

Show work please..

Answer 1

here,

mass of the block , m = 3.4 kg

force acting on the block , F = 29.0 N

frictional force acting on it , ff = 7 N

A)

let the horizontal accelration be a

then , equating the forces

F - ff = m * a

29 - 7 = 3.4 * a

a = 6.47 m/s^2

the horizontal accelration of the block is 6.47 m/s^2

B)

initial velocity , u = 0

time , t = 2.5 s

let the velocity after 2.5 s be v

using first equation of motion

v = u + a * t

v = 2.5 * 6.47

v = 16.18 m/s

the velocity after 2.5 s is 16.18 m/s