Answer:
945 j
Explanation:
You have just given the ball kinetic energy, which is given by the following equation:
KE= 1⁄2 m v2 = 1⁄2 (2.1 kg)(30 m/s)2 = 945 Joules
2.c
3.b
1.a
......................................................................................................................................................
Answer:
4462.0927 W
Explanation:
= Emissivity of the panel = 1
= Stefan-Boltzmann constant = 
T = Temperature = (273.15+6)
Area of the panel is given by

The power radiated is given by

The power radiated from each panel is 4462.0927 W
Answers:
kinetic energy lost = 86.4J
Explanation:
let Kf be the kinetic energy after the collision and Ki be the kinetic energy before the collision. let the 3kg car be 1 and 2kg car be 2.
Kf = K1(f) + K2(f)
Ki = K1(i) + k2(i)
loss in kinetic energy = Kf - Ki
= 1/2(3)(2.20)^2 + 1/2(2)(2.20)^2 - 1/2(3)(7)^2 - 1/2(2)(-5)^2
= 12.1 - 98.5
= -86.4 J
therefore, the kinetic energy lost in the collision is 86.4 J.
The cyclist's final velocity is 10 m/s.
From the question,
We are to determine the cyclist's final velocity.
<h3>Linear motion</h3>
From one of the equations of motion for linear motion, we have

Where
v is the final velocity
u is the initial velocity
a is the acceleration
and t is the time
From the given information,
The cyclist starts at rest, this means the initial velocity is 0 m/s
That is,
u = 0 m/s
Also
a = 0.5 m/s²
and t = 20 s
Putting the parameters into the equation, we get



Hence, the cyclist's final velocity is 10 m/s.
Learn more on linear motion here: brainly.com/question/19365526