Question

I need help solving theses problems please and thank you.

1. When you drop a ball it accelerates downward at 9.8 m/s. If you instead throw it downward, then its acceleration immediately after leaving your hand, assuming no air resistance, is A. 9.8 m/s2 B. More than 9.8 m/s C. Less than 9.8 m/s D. Cannot say, unless the speed of the throw is given. 2. A heavy rock and a light rock in free fall (zero air resistance) have the same acceleration. The reason the heavy rock doesn't have a greater acceleration is that the A. Force due to gravity is the same on each B. Air resistance is always zero in free fall C. Inertia of force to mass is the same D. Ratio of force to mass is the same E. None of these 3. A cannonball is fired horizontally at 10 m/s from a cliff. Its speed one second after being fired is about A. 10 m/s B. 14 m/s C. 16 m/s 20 m/s E. The answer is not provided, and I do not know E. The answer s not provided, and 1 do nod

Answer 1

Solution :- the acceleration will be 9.8 M/S2. As the ball is left from hand so it only have force of gravity hence acceleration 9.8 m/s2 .Go for option A.

S. The force due to gravity is not same on both of them instead of the ratio of force to mass is same because it is gravitational acceleration. Go for option D.

3. When the ball is thrown from cliff it will have projectile motion. Instead of horizontal velocity it also has vertical velocity.

The horizontal velocity is equal to 10 m/s while the vertical velocity we can find using equation of motion

V = u + at. So it comes to be 9.8 m/s.

So net speed will be the vector sum of this therefore it is equal to 14.001 m/s. So to for option B.