Answer:
Input power, Ip = 4 Watts
Explanation:
Given the following data;
Power output = 0.8 Watts
Efficiency = 20%
To find the power input of the sunlight onto the solar panel;
Mathematically, the efficiency of a machine is given by the formula;
Substituting into the formula, we have;
Cross-multiplying, we have;
Input power, Ip = 4 Watts
I don't think that 4m has anything to do with the problem.
anyway. here.
A___________________B_______C
where A is the point that the train was released.
B is where the wheel started to stick
C is where it stopped
From A to B, v=2.5m/s, it takes 2s to go A to B so t=2
AB= v*t = 2.5 * 2 = 5m
The train comes to a stop 7.7 m from the point at which it was released so AC=7.7m
then BC= AC-AB = 7.7-5 = 2.7m
now consider BC
v^2=u^2+2as
where u is initial speed, in this case is 2.5m/s
v is final speed, train stop at C so final speed=0, so v=0
a is acceleration
s is displacement, which is BC=2.7m
substitute all the number into equation, we have
0^2 = 2.5^2 + 2*a*2.7
0 = 6.25 + 5.4a
a = -6.25/5.4 = -1.157
so acceleration is -1.157m/(s^2)
The best answer to go with is b
he speed of the student relative to shore is
v_ up = v- vs
v _down = v+ vs
The time required to travel distance d upstream
is
t_up = d/ v_up = d/ v- vs
(2)
The time required to swim the same distance d downstream is
t_down = d/ v_down = d/ v+ vs
