Answer:
Net force = 800 – 650
= 150 N
150 = (800 ÷ 9.8) a
a = 1470 ÷ 800
= 1.8375 m/s^2, downwards
Answer:
Explanation:
Given mass of grindstone 
radius of stone 
angular speed of disc 
Steel Axle applying a force of 
coefficient of kinetic friction 
Frictional Torque applied by steel is given by


where
=frictional force



Torque is also given by

where
=angular acceleration
I=moment of Inertia




no. energy is not created or destroyed, just transformed.
a hot light source is less efficient than a cold one ... heat is not light ...
KE=0.5 * mass* speed^2
Convert 72 km/h to m/s by dividing it by 3.6
72/3.6= 0.277778m/s
KE=0.5*1500*0.277778
= 208.3335J
= 208J