Particles can either have a positive or negative charge.
Answer:
Cu 8.92
Explanation:
The formula for density is mass/volume. If you were to divide 62.44 by 7, you would get 8.92. Since copper is the only metal in this table that has a density of 8.92, that is the answer.
Answer
Given,
Energy absorbed, 
Energy expels,
Temperature of cold reservoir, T = 27°C
a) Efficiency of engine



b) Work done by the engine



c) Power output
t = 0.296 s



initial velocity of the car given as

final velocity is given as

as we know that

now we can convert final speed into m/s

now acceleration is rate of change in velocity



so the acceleration of the car is 3 m/s^2
1 watt = 1 joule per sec
11,000 Watts = 11,000 joules per sec
The frequency doesn't matter.