Can anyone solve this problem for me? A 6.0-kg block slides 1.5 m down a frictio

Question

Can anyone solve this problem for me?

A 6.0-kg block slides 1.5 m down a frictionless incline that makes an angle of 60 degree with the horizontal. (a) Draw the free-body diagram of the block, and find the work done by each force when the block slides 1.5 m (measured along the incline). (b) What is the total work done on the block? (c) What is the speed of the block after it has slid 1.5 m, if it starts from rest? (d) What is its speed after 1.5 m, if it starts with an initial speed of 2.0 m/s? [Answer: (a) Wweigh =0.10 kJ, Wnormal = 0J (b) 0.10 kJ (c) 5.00 m/s (d) 5.40 m/s]

Explanation / Answer

The answer given by your sheet for A for Work by gravity cannot be right.

(A) mgh=(6kg)(-9.81)(0-1.5sin(60)=

76.46 J for gravity

There is no acceleration by force normal so its 0 J

(B) is just 76.46 J

(C) 1/2mv^2 final=mgh initial

which is just .... 1/2v^2=gh so v final = square root of (2gh)

v final= square root (2(9.81)(1.5sin(60))=

5.04 m/s

(D)1/2m( v^2 final - v^2 initial) = mgh

which is just.... 1/2(v^2 final - v^2 initial) = gh v final= square root( 2gh+ v^2 initial)= square root [(2*9.81*1.5sin(60))+(2)^2]=

5.43m/s

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