An object with a mass of #7 kg# is on a surface with a kinetic friction coefficient of # 8 #. How much force is necessary to accelerate the object horizontally at # 32 m/s^2#?

2 Answers
Jan 14, 2018

Answer:

#784 N#

Explanation:

enter image source here As,the object is going on a horizontal surface,frictional force acting on it will be #f = u*N# or #umg# i.e #(8*7*10#) N or, 560 N

So,le't's assume we will be requiring a force of F to cause an acceleration of 32 SI units on it.

so,we can write, #F-f = m*a#(where, m is the mass of the object and a is its acceleration)

so, #F=(560+7*32)# N or, #784 N#

Jan 14, 2018

Answer:

The force is #=772.8N#

Explanation:

The mass of the object is #m=7kg#

The acceleration is #a=32ms^-2#

The coefficient of kinetic friction is

#mu_k=F_r/N=8#

The normal force is #N=7gN#

The frictional force is #F_r=mu_k xx N=8*7g=56gN#

The force necessary to accelerate the object is #=FN#

The acceleration due to gravity is #g=9.8ms^-2#

According to Newton's Second Law

#F-F_r=ma#

#F=ma+F_r=((7xx32)+(56g))N=772.8N#