Answer:
39 m/s
Explanation:
Hi!
The equation of motion of the ball is:

Where y_0 is the initial horizontal position, which we will take as zero.
v_0y is the initial velocity and t is the time
To find the initial velocity we will set y(7.96s) = 0

Answer:
t = 180 / 1.4 = 129 sec (time to swim horizontally across river)
S = 129 sec * V where V is speed of current and S is the distance he will be carried downstream
The problem does not specify V the speed of the river
Answer:
mass
Explanation:
Mass (M) is the measure of the amount of matter in an object. Mass is measured in grams (g). Mass is measured on a balance by comparing the object against other objects with known masses.
Answer:
13.23J
Explanation:
PE = m*g*h
PE = (3 kg ) * (9.8 m/s/s) * (0.45 m)