A 30 kg child descends a slide 6.0m high and reaches the bottom with a speed of 3.2m/s

need help on following questions please tell me the formula for all of them
(A) what is the potential energy at the top
(B) what is the kinetic energy at the bottom
(C) What is the number of joules of heat generated
(D) What is the efficiency of this energy conversion

A) Potential Energy at the top = mgh = 30(9.8)(6) = 1764J
B) Kinetic Energy at the bottom = (1/2)mv^2 = (1/2)(30)(3.2)^2 = 153.6J
C) Joules of heat generated = A - B = 1764 - 153.6 = 1610.4
D) Efficiency = Energy final/ Energy initial

D depends on if you are referring to the efficiency of energy conversion into heat or kinetic.

For kinetic = 153.6/1764
For Heat = 1610.4/1764

Since it is a boy sliding I think you want kinetic but I'm not sure

(A) what is the potential energy at the top ------ mgh =30*9.8*6 = 1764 J
(B) what is the kinetic energy at the bottom. 0.5mv² = 153.6
(C) What is the number of joules of heat generated?
Difference between the initial and final energy = 1764 – 153.6 =

(D) What is the efficiency of this energy conversion?
Final energy /initial energy = 153.6 / 1764 =
153.6 / 1764= 0.087
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If you use ΔKE + Δ PE = 0

a)
(0.5mv^2 - 0 ) + (0-mgh) = 0 (Potential energy is mgh)
0.5*30*3.2^2 = mgh
153.6=mgh

b)
KE at bottom = 153.6