Answer:
mj = 53.3kg
Explanation:
Since both gravitational energies are the same:
Eb = Ej => mb*g*hb = mj*g*hj
Solving for mj:
mj = mb*hb/hj = 80*2.4/3.6
mj = 53.3kg
121 is the answer to your question
No, both the cars do not have the same velocity.
Velocity is a vector quantity and it is the rate of change of displacement with time or change in speed with direction.
Velocity has both magnitude and direction. So when you are in a car going 70 km/h and another car goes in the opposite direction at 70 km/h their velocities are different.
How?
Consider your car as moving in the positive direction, so its velocity will be 70 km/h and for the car moving in the opposite direction, since the direction is opposite, the velocity of that car will be -70 km/h. This is because, the velocity is a vector quantity that has both magnitude and direction. For one car, the direction is positive and for the other one the direction is negative.
Well, if they're deaf then they don't need to take a step at all