The train’s average speed is 80km/h
Answer:
√(6ax)
Explanation:
Hi!
The question states that during a time t the motorcyle underwent a displacement x at constant acceleration a starting from rest, mathematically we can express it as:
x=(1/2)at^2
Then the we need to find the time t' for which the displacement is 3x
3x=(1/2)a(t')^2
Solving for t':
t'=√(6x/a)
Now, the velocity of the motorcycle as a function of time is:
v(t)=a*t
Evaluating at t=t'
v(t')=a*√(6x/a)=√(6*x*a)
Which is the final velocity
Have a nice day!
Answer:
the claim is not valid or reasonable.
Explanation:
In order to test the claim we will find the maximum and actual efficiencies. maximum efficiency of a heat engine can be found as:
η(max) = 1 - T₁/T₂
where,
η(max) = maximum efficiency = ?
T₁ = Sink Temperature = 300 K
T₂ = Source Temperature = 400 K
Therefore,
η(max) = 1 - 300 K/400 K
η(max) = 0.25 = 25%
Now, we calculate the actual frequency of the engine:
η = W/Q
where,
W = Net Work = 250 KJ
Q = Heat Received = 750 KJ
Therefore,
η = 250 KJ/750 KJ
η = 0.333 = 33.3 %
η > η(max)
The actual efficiency of a heat engine can never be greater than its Carnot efficiency or the maximum efficiency.
<u>Therefore, the claim is not valid or reasonable.</u>
It would be B since it starts with the solar energy which is converted to electricity with the solar panels, which then creates mechanical energy for the fans blades to move and sound for the radio.
Hope that helps :)
Complete Question:
The elastic energy stored in your tendons can contribute up to 35 % of your energy needs when running. Sports scientists have studied the change in length of the knee extensor tendon in sprinters and nonathletes. They find (on average) that the sprinters' tendons stretch 43 mm , while nonathletes' stretch only 32 mm . The spring constant for the tendon is the same for both groups, 
. What is the difference in maximum stored energy between the sprinters and the nonathlethes?
Answer:
Explanation:
Sprinters' tendons stretch, 
Non athletes' stretch, 
Spring constant for the two groups, k = 31 N/mm = 3100 N/m
Maximum Energy stored in the sprinter, 
Maximum energy stored in the non athletes, 
Difference in maximum stored energy between the sprinters and the non-athlethes:
