Question

The table shows the mechanical energy and velocity of a rock that was thrown four times. The rock has a mass of 2.4 kg.

Trial Mechanical Energy Velocity

1 32 7.0

2 34 2.0

3 35 6.0

4 31 3.0

During which trial was the rock the highest above the ground?

A. 1

B. 2

C. 3

D. 4

Answer 1

the second problem is b

Answer 2

In each case we will find the Kinetic energy and find its difference with total mechanical energy

As we know that

Potential Energy = Mechanical Energy - Kinetic Energy

so if object will have more potential energy then it will have more height

now for potential energy in each case

1. Kinetic energy is given as

`KE = (1)/(2) (2.4) 7^2 = 58.8 J`

now PE = 32 - 58.8 = -26.8 J[/tex]

2. Kinetic energy is given as

`KE = (1)/(2) (2.4) 2^2 = 4.8 J`

now PE = 34 - 4.8 = 29.2 J[/tex]

3. Kinetic energy is given as

`KE = (1)/(2) (2.4) 6^2 = 43.2 J`

now PE = 35 - 43.2 = -8.2 J[/tex]

4. Kinetic energy is given as

`KE = (1)/(2) (2.4) 3^2 = 10.8 J`

now PE = 31 - 10.8 = 20.2 J[/tex]

So here maximum potential energy in case 2

So maximum height will be in case 2