The amount of water needed is 287 kg
Explanation:
The amount of energy that we need to produce with the power plant is
We also know that the power plant is only 30% efficient, so the energy produced in input must be:
The amount of water that is needed to produce this energy can be found using the equation
where:
m is the amount of water
is the specific heat capacity of water
is the increase in temperature
And solving for m, we find:
Learn more about specific heat capacity:
#LearnwithBrainly
Answer:
The work done by this force can be found via the following formula
Explanation:
Alternatively, the work done by the object is equal to the elastic potantial energy done by the spring.
Answer:
The rifle barrel must be pointed at a height of 4.45cm above the target so that the bullet hits dead center.
Explanation:
First, we need to sketch the situation so we can have a better idea of what the problem looks like (Refer to uploaded picture).
So as you may see in the drawing, when pointing the rifle to the target, we can see it as a triangle, but in reality, the bullet will have a parabolic trajectory. Both points of view will help us determine what the height must be. In order to find it, we need to first determine at what angle the bullet should be shot. In order to do so we can use the range formula, which looks like this:
Where R is the range of the bullet (this is how far it goes before it has the
same height it was shot from), v is the original speed of the bullet, θ is the angle at which the bullet is shot and g is the acceleration of gravity.
We can solve this equation for theta, so we get:
so now we can substitute the given data:
so we get:
θ=0.05614°
once we get the angle, we can look at the triangle diagram. From the drawing we can see that we can use the tan function to find the height:
so we can solve this for h, so we get:
which yields:
or
