Answer:
The answer is "Repetition"
Explanation: when you say something more than 3 times, is called repetiton
Answer:
Explanation:
Sam mass=75kg
Height is 50m
20° frictionless slope
Horizontal force on Sam is 200N
According to the work energy theorem, the net work done on Sam will be equal to his change in kinetic energy.
Therefore
Wg - Ww =∆K.E
Note initial the body was at rest at top of the slope.
Then, ∆K.E is K.E(final) - K.E(initial)
K.E Is given as ½mv²
Since initial velocity is zero then, K.E(initial ) is zero
Therefore, ∆K.E=½mVf²
Wg is work done by gravity and it is given by using P.E formulas
Wg=mgh
Wg=75×9.8×50
Wg=36750J
Ww is work done by wind and it's is given by using formulae for work
Work=force × distance
Ww=horizontal force × horizontal distance
Using Trig.
TanX=opposite/adjacent
Tan20=h/x
x=h/tan20
x=50/tan20
x=137.37m
Then,
Ww=F×x
Ww=200×137.37
We=27474J
Now applying the formula
Wg - Ww =∆K.E
36750 - 27474 =½×75×Vf²
9276=37.5Vf²
Vf²=9275/37.5
Vf²= 247.36
Vf=√247.36
Vf=15.73m/s
Answer:
2.24 m/s
Explanation:
resolving force of 29.2 N in x component
Fx = 29.2 cos 57.7
Fx = 15.6N
as force of friction is 12.7 N hence net force which produces acceleration is
15.6-12.7=2.9 N
by Newton 's law a=f/m
a= 2.9/6.87=0.422 m/s^2
now equation of motion is
v^2= U^2+2as
= 0^2+2(.422)(5.93)
v^2=5.00
v=2.24 m/s
Answer:
D) Fusion requires high temperatures and pressures, so how have they reduced the energy cost for it?
Explanation:
Fusion requires high temperatures and pressure for initiation of reaction . There is no chain reaction in it so there is no problem of controlling the problem . On the other hand , the reaction tends to stop as soon as temperature goes down due to heat getting dissipated . There is no problem of fuel as its fuel is deuterium which is present in nature in large amount . The question which is pertinent is that the cost involved in attaining so high temperature is very high so is it cost effective to produce energy by incurring so much of cost . Producing energy by using so much of energy in the beginning appears to be preposterous.
Answer:
B
i am not fully sure but i believe its the most accurate its either A or B
