Assuming it is on a horizontal surface:
friction = μR
R = 20g (g is gravity 9.81)
so Friction = 0.085 x 20g
Work done is force x distance
so Work done = 0.085 x 20g x 28
= 466.956 J
The answer is B
second law
D)
Explanation:
Coz the position changes with time but the position change is not constant throughout time So, D) does not have constant velocity
It will take 6.42 s for the ball that is dropped from a height of 206 m to reach the ground.
From the question given above, the following data were obtained:
Height (H) = 206 m
<h3>Time (t) =? </h3>
NOTE: Acceleration due to gravity (g) = 10 m/s²
The time taken for the ball to get to the ground can be obtained as follow:
H = ½gt²
206 = ½ × 10 × t²
206 = 5 × t²
Divide both side by 5

Take the square root of both side

<h3>t = 6.42 s</h3>
Therefore, it will take 6.42 s for the ball to get to the ground.
Learn more: brainly.com/question/24903556