Physics Work Question?

Question

A(n) 646 kg elevator starts from rest. It moves
upward for 3.41 s with a constant acceleration
until it reaches its cruising speed of 1.86 m/s.
The acceleration of gravity is 9.8 m/s^2
Find the average power delivered by the
elevator motor during this period. Answer in
units of kW.

and

Wayne pulls a 407 N sled along a snowy path
using a rope that makes a 37 degree angle with the
ground. Wayne pulls with a force of 81.7 N.
The sled moves 26.1 m in 2.3 s.
What is Wayne's power? Answer in units
of W.

I got 5.887644 kW for the first question, and 709.6280791 W for the second question, but both were wrong.
Could someone help me with these two questions? i would like work and an answer please, thanks :)

Answer 1

answer is P(av) = 6.215 KW
1) lift acceleration = a = [v(final) - 0] /t = 1.86/3.41 = 0.545 m/s^2
average power = apparent weight * average speed
apparent weight net force = m(a+g)
==============================
lift acceleration up = ma
acceleration of gravity up = - mg
net up = ma – (-mg)
apparent weight = R = Fn = m (a+g)
==============================
P (av) = {ma + mg} [v+u]/2
P (av) = 646*{0.545 +9.8}[1.86]/2
P (av) = 6.215 kilo watt
============
2) power = 740.42 watt
F- applied = 81.7
component of force along displacement = 81.7 cos 37
other componemt adds to weight (would have been important had there been friction involved)
W = work done by man = 81.7 cos 37 * 26.1 N
Power (man) = W/t = 81.7 cos 37 * 26.1 /t
P = 1702.99 / 2.3 = 740.42 watt

Answer 2

a = (v1 - v0)/t
h1 = h0 + v0t + (1/2)at^2
E = mgh1 + (1/2)mv1^2
W = E/t
W = m(gh1 + (1/2)v1^2)/t
W = m(g(h0 + v0t + (1/2)at^2) + (1/2)v1^2)/t
W = m(g(h0 + v0t + (1/2)((v1 - v0)/t)t^2) + (1/2)v1^2)/t
W = m(g(h0 + v0t + (1/2)(v1t - v0t)) + (1/2)v1^2)/t
W = (646 kg)((9.8 m/s^2)(0 + 0 + (1/2)((1.86 m/s)(3.41 s) - 0)) + (1/2)(1.86 m/s)^2) / (3.41 s)
W = (646 kg)(31.07874 m^2/s^2 + 1.7298 m^2/s^2) / (3.41 s)
W = (646 kg)(32.80854 m^2/s^2) / (3.41 s)
W ≈ 6,215.342 J/s ≈ 6.215 KW

(81.7 N)(cos37°)(26.1 m) / (2.3 s) ≈ 740.4289 J/s ≈ 740 W

Answer 3

1)
v=u+at
a=v-u/t
a=1.86/3.41
a=.54m/s2

s=ut+at^2/2
s=.54*3.41*3.41/2
s=3.17

P=W/t
P=Fs/t
P=646*9.8*3.17/3.41
P=5887.6W=5.887kW

2)
w=FscosA
P=W/t
P=81.7*26.1*4/5*1/2.3
P=741.69W