An inventor claims to have devised a cyclical engine for use in space vehicles that operates with a nuclear-fuelgenerated energy
1 answer:
Answer:
Valid
Explanation:
to determine if the claim is valid, we compare the efficiency of the device to that of a Carnot engine.
The following data were given
High Temperature = 920R,
Low temperature =490R
work=4.5hp =4.5*2544.5=11450.25Btu/h
low heat Ql heat= 15000Btu/h
High heat Qh=work +Ql=11450.25Btu/h+15000Btu/h=26450.25Btu/h
Next we cal calculate the efficiency of the Carnot engine
Hence the maximum efficiency at the given temperature is 47%
Next we calculate the efficiency of the device
which is 43%
since the maximum efficiency of 47% is not exceeded, we can conclude that the claim is valid
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Answer:
T= 1 s
Explanation:
Given that
When x= cm ,T= 1
we know that time period of spring mas system given as
T= Time period
m= mass
k=spring constant
So from above equation we can say that time period of system does not depends on the value of x.
So when x= 10 cm ,still time period will be 1 s.
T= 1 s
Answer:
The acceleration of the crate is 1.8 m/s² so the answer is a.
Explanation:
The very first thing you must do when solving this problem is to draw a free body diagram. (The body diagram is attached to this answer)
So once we got the free body diagram, we can analyze it and build our sum of forces in the x and y directions. Notice that according to the diagram, there are 4 forces to this problem, Normal (N), Weight (W), kinetic friction (fk) and the 750N force.
As one may see in the free body diagram, two of the forces are vertical forces: N and W, so we can use them to build a sum of forces:
Starting with the sum of forces in the y-direction, we get:
Σ=0
We set the sum equal to zero because there is no movement in the y-direction, so the system is in vertical equilibrium.
so the sum will be:
when solving for N we get that:
N=W
where W is found by multiplying the mass of the crate by the acceleration of gravity:
N=250kg*9.8m/s²
N=2450N
Once we found the normal force, we can use it to find the kinetic friction which is given by the following formula:
μ
where μ is the kinetic friction coefficient.
So we get that the kinetic friction is:
so
With this information we can go ahead and find the sum of horizontal forces:
Σ=ma
In this case the sum is equal to mass times acceleration because the crate is moving horizontally due to the action of a force, so it will have an acceleration.
so the sum of forces look like this:
750N-=ma
so
750N-294N=(250kg)a
when solving for a we get:
so the crate's acceleration is 1.82m/s².
