There is no equation here
Answer:
20 Joules
Explanation:
Work is done whenever a force moves a body through a certain distance in the direction of the force. So, work done is the product of force and distance moved.
Therefore, we have;
Work done = Force x distance
i.e Wd = Fs
Given that: F = 20 N and s = 1 m, then;
Wd = 20 N x 1 m
= 20 Nm
The work done by the father is 20 Joules(Nm).
Answer:
E = 13.2 kWh
, Cost = $ 10.8
Explanation:
We can look for the consumed energy from the expression of the power
P = W / t
The work is equal to the variation of the kinetic energy, for which
P = E / t
E = P t
look for the energy consumed in one day and multiply by the days of the month in the month
E = 110 4 30
E = 13200 W h
E = 13.2 kWh
the cost of this energy is
Cost = 0.9 12
Cost = $ 10.8
Assume the snow is uniform, and horizontal.
Given:
coefficient of kinetic friction = 0.10 = muK
weight of sled = 48 N
weight of rider = 660 N
normal force on of sled with rider = 48+660 N = 708 N = N
Force required to maintain a uniform speed
= coefficient of kinetic friction * normal force
= muK * N
= 0.10 * 708 N
=70.8 N
Note: it takes more than 70.8 N to start the sled in motion, because static friction is in general greater than kinetic friction.
The stone's altitude at time 
is given by
where 
is the acceleration due to gravity. The stone reaches the ground when 
:
