A 1.15 kg grinding wheel 20 cm in diameter is spinning clockwise at rate of 25 revolutions per second. When the power to the grinder is turned off, the grinding wheel slows with constant angular acceleration and takes 1.5 minutes to come to rest. What was the linear acceleration (in m / sec²) of grinding wheel as it comes to rest if we take a clockwise rotation as positive?

Answer 1

Choose...

How many revolution did the wheel make during the time it was coming to rest?

Answer 2

Choose...

What was the angular acceleration (in rad / sec²) of grinding wheel as it comes to rest if we take a counterclockwise rotation as positive?

(a) Linear acceleration of the wheel is 0.175 m/s²

(b) The angular acceleration is -1.75 rad/s²

Explanation:

Given;

mass of the grinding wheel, m = 1.15 kg

diameter of the grinding wheel, d = 20 cm

radius of wheel, r = 10 cm = 0.1 m

angular speed of the wheel, ω = 25 revolutions per second

time for the wheel to come to rest, t = 1.5 minutes

The linear speed is calculated as;

v = ωr

(a) Linear acceleration of the wheel is calculated;

(b) The angular acceleration is calculated as;

jupiter is the largest planet in our solar system, having a mass and radius that are respectively, 318 and 11.2 times that of earth. suppose that an object falls from rest near the surface of each planet and that the acceleration due to gravity remains constant during the fall. each object falls the same distance before striking the ground. determine the ratio of the time of fall on jupiter to that on earth.

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =