Can someone help me with part e) ? :) Look at the system in the photo. Object B

Question

Can someone help me with part e) ? :)

Look at the system in the photo. Object B has the mass 10.0 kg.

a) What will the acceleration be if m=4.0 kg and ?k=0.20

b) What is the pulling force in the string in part a) ?

c) what is the acceleration of the system if m=35kg and ?k =0,080?

d) Now the system moves to the left with constant speed when m=28kg. What is the ?k and the pulling force in the force ?

e) Now: m=20 kg and ?s =0,45. An extra mass is loaded on object B untill the system starts to move. How much extra mass is needed? and what will the acceleration be if ?k = 0,37 ?

Explanation / Answer

Solution:

e)

Solution: Let extra mass added = X

Total hanging mass = 10 + X

Weight of the hanging mass = (10+X)g

us= 0.45

Friction force = us mg cos35 = (0.45)(20)g cos35

The force equations: T- us mg cos 35-mg sin35=0 => T = us mg cos35 + mg sin 35 =(0.45)(20)(g)cos35 + (20g)(sin35) =18.4 g newtons

And for the hanging mass: (10+X) g = T

-mg sin35-uk mg cos 35 + T = ma (acceleration is assumed to be in the direction of T, up the ramp)

and -T + (10+X)g =(10+X)a

adding these two equations, - mg sin35-uk mg cos 35 + (10+X)g =20a+(10+8.84)a

                                              =-mg sin35 –ukmg co35 +(10+8.84)g =38.84 a

                                              = -171.8 + 184.65 =38.84a

                                             = 356.5 =38.84a

=>acceleration =a = 356.5/38.84

                               = 9.18 m/s2

                                                = 9.2 m/s2

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.