Answer:0.6kw
Explanation:
Power=force×velocity
Power=20×30=600w
In kw it's going to be 600/1000=0.6kw
<h2>
Answer: B) It would be best to use a concave mirror, with the object to be ignited positioned halfway between the mirror and its center of curvature. </h2>
Explanation:
To start a fire it is more optimal to use a concave mirror than a plane mirror. This is because the concave mirror allows concentrating sunlight at a point (the focal point) on an object that acts as fuel and ignite the fire there.
For this it is necessary the object to be positioned between the center of curvature of the mirror and the mirror (its focus). Thus the rays of the Sun, when converging on the focus, will heat the object and make it burn.
Hence, the correct option is B.
Complementary is essentially two things that are "combined" with one another (complement one another) to make a bigger piece or make it better.
Answer:4.22 J
Explanation:
Given
mass of pitcher 
Force applied 
distance moved 
Applying work-Energy theorem which states that work done by all the forces is equal to the change in kinetic energy of the object
Work done by force 
W=
change in kinetic Energy =
K.E.-0=
K.E.=
General internal energy expression:
Uf = (Ui-W) + Q
Where Uf = Final internal energy, Ui = Initial internal energy, W = Work done, Q = Heat added
But,
Uf -Ui = ΔU = 36 J, W = 17 J. Then,
ΔU = -W +Q => Q = ΔU+W = 36+17 = 53 J
Therefore, heat added to the system is 53 Joules
