A body is accelerated continuously. What is the form of the graph? ОА.
cubic
OB.
inverse
O c.
linear
OD.
quadratic

B would be the answer

a) 4,320 J

b) 8 m

c) 4,320 J

Explanation:

1) Data:

Part a) smooth ice:

m₁ = 20 kgm₂ = 40 kgv = 12 m/sKE = ?

Part b) rough ice:

F = 540 Nstopping distace, d = ?

Part c) rough ice:

W = ?

2) Solution:

a) KInetic energy:

KE = (1/2)mv² = (1/2) [m₁ + m₂] v² = (1/2) [20kg + 40kg] (12 m/s)² = 4,320 J

b) Distance to stop (Vf = 0)

Since, you have average force (opposing force) you can calculate average acceleration (deceleration)

F = m×a ⇒ a = F/m = F / (m₁ + m₂) = 540 N / (20 + 40 kg) = 9 m/s²

Now, use kinematic equation for uniformly decelarated motion:

Vf²= Vo² - 2ad ⇒ d = [Vo² - Vf²] /(2a) = [ (12m/s)² - 0 ] / (2×9m/s²) = 8 m

c) Work, W

Again, using average force, you can calculate work done by the force:

W = F × d = 540N × 8 m = 4,320 J

Note that this result confirms our calculations are fine, as the work done by the rough ice is equal to the initial kinetic energy, condition of energy conservation law.