The principle of resistance training that suggests that muscles should be gradually required to do more than they are used to doing is D. OVERLOAD.
The principle of overload states that a greater than normal stress or load on the body is required for training adaptation to take place.
Overload refers to the amount of load or resistance, providing a greater stress, or load, on the body than it is normally accustomed to in order to increase fitness.
Answer:
Collision force will be same in both the cases.
Explanation:
A perfectly inelastic collision is said to take place when a system loses the amount of its Kinetic Energy at its maximum. In a perfectly inelastic collision, the colliding particles stick to each other. In such a collision, kinetic energy is lost by combining the two bodies with each other.
In situation 1:
Speed of Car A, 
Speed of Car B, 
Relative speed of car A and car B, 
Now, in the situation 2:
Speed of car A, 
Speed of car B, 
Relative speed of car A and car B, 
Therefore, Car A and Car B both have the same relative speed, v = 10 m/s
Technically all 3 of those would be correct answers. But applying the brakes would probably be the correct answer if all of the above isn't a answer.
2.3 seconds
Ignoring air resistance, the flight time is merely a function of gravity and vertical velocity. The vertical velocity will be the initial velocity multiplied by the sine of the angle above the horizon. So:
V = sin(72)*12 m/s
V = 0.951056516 * 12 m/s
V = 11.4126782 m/s
Gravitational acceleration is 9.8 m/s, so divide the vertical velocity by gravitational acceleration to get how long it takes for the ball to reach its apex.
11.4126782 m/s / 9.8 m/s^2 = 1.164559 s
And the old saying "What goes up, must come down" really applies here. And conveniently, it's also symmetric, in that the time it takes to fall will match the time it takes to reach its apex. So multiply the time by 2.
1.164559 s * 2 = 2.329117999 s
Rounding the result to 2 significant figures gives 2.3 seconds.
Scientists believe that um the big bang created the earth