Lars is standing near the edge of a 90-meter cliff. He throws a ball upward, but does not catch it, and it falls to the bottom of the cliff face. From when he threw the ball upward to when it hit the ground below, 5.55 seconds passed. What was the initial vertical velocity of Lars' throw? a. -43 m/s
b. -11 m/s
c. 43 m/s
d. 11 m/s

c. 43 m/s

Explanation:

Given the following data;

Displacement, S = 90 meters

Time, t = 5.55 seconds

To find the initial velocity;

We would use the second equation of motion given by the formula;

Where;

We know that acceleration due to gravity is -9.8m/s² because the direction is downward.

Substituting into the equation, we have;

Rearranging the equation, we have;

Initial velocity, u = 43.41 ≈ 41 m/s

c.the charges if the proton and electron and gravity

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.