Im not 100% sure you have to tell me if im wrong or not.
D
B
C
Answer:
Though you have not gave the choices, I do believe it is “testing”
Explanation:
Radioactive "decay" means particles and stuff shoot OUT of a nucleus.
After that happens, there's less stuff in the nucleus than there was before.
So the new mass number is always less than the original mass number.
Answer:Water Only
Explanation:
Given
vessel is insulated therefore no heat can be added or removed i.e. heat exchange is zero
If hot water at 
is mixed with cold water at 
then at equilibrium vessel contains only water and final temperature of water will be between and
Heat released by hot water is equal to heat gain by cold water .
Answer:
(a) 10 m/s
(b) 22.4 m/s
Explanation:
(a) Draw a free body diagram of the car when it is at the top of the loop. There are two forces: weight force mg pulling down, and normal force N pushing down.
Sum of forces in the centripetal direction (towards the center):
∑F = ma
mg + N = mv²/r
At minimum speed, the normal force is 0.
mg = mv²/r
g = v²/r
v = √(gr)
v = √(10 m/s² × 10.0 m)
v = 10 m/s
(b) Energy is conserved.
Initial kinetic energy + initial potential energy = final kinetic energy
½ mv₀² + mgh = ½ mv²
v₀² + 2gh = v²
(10 m/s)² + 2 (10 m/s²) (20.0 m) = v²
v = 22.4 m/s
