You push a 400 kg car for 6 m with a force of 300 N? What is the car’s final speed if all your work became kinetic energy? Group of answer choices

3 m/s

5.8 m/s

80 m/s

0.40 m/s

3m/s

Explanation:

KE = ¹/₂ mv²

But workdone = F x d

Workdone = 300 x 6

Workdone = 1800J

Now per the question.

assuming

workdone= KE

Then

KE = ¹/₂ mv²

1800J = ¹/₂ 400kg x V²

3600J = 400 x V²

3600J / 400kg = V²

9 =V²

V =√(9)

V = 3m/s

The initial velocity was 9.39 m/s

Explanation:

Lets explain how to solve the problem

The ball is thrown straight upward with initial velocity u

The ball reaches a maximum height of 4.5 m

At the maximum height velocity v = 0

The acceleration of gravity is -9.8 m/s²

We need to find the initial velocity

The best rule to find the initial velocity is v² = u² + 2ah, where v is

the final velocity, u is the initial velocity, a is the acceleration of

gravity and h is the height

⇒ v = 0 , h = 4.5 m , a = -9.8 m/s²

⇒ 0 = u² + 2(-9.8)(4.5)

⇒ 0 = u² - 88.2

Add 88.2 to both sides

⇒ 88.2 = u²

Take square root for both sides

⇒ u = 9.39 m/s

The initial velocity was 9.39 m/s