Answer:
the speed of the tip of a blade 10 s after the fan is turned off is 16.889 m/s.
Explanation:
Given;
diameter of the ceiling fan, d = 90 cm = 0.9 m
angular speed of the fan, ω = 64 rpm
time taken for the fan to stop, t = 28 s
The distance traveled by the ceiling fan when it comes to a stop is calculated as;
The speed of the tip of a blade 10 s after the fan is turned off is calculated as;
Therefore, the speed of the tip of a blade 10 s after the fan is turned off is 16.889 m/s.
Answer:
h = 1.8 m
Explanation:
The initial velocity of the glove, u =- 6 m/s
We need to find the maximum height of the glove. Let it is equal to h. Using equation of kinematics. At the maximum height v = 0
, h is the maximum height and a = -g
Hence, it will go up to a height of 1.8 m.
AS
work done =W = F.d = F d cosФ (Ф is angle between force F and displacement d) If a body/object is moving on a smooth surface (friction-less surface ) .There is no force acting on that body. F=0 so W=FdcosФ= (0)dcosФ ⇒ W=0
Now if a body is facing some amount of force but under the action of force there is no displacement covered. d=0 so W =FdcosФ= F(0)cosФ ⇒W=0
example: A person is applying a force on rigid wall but wall remains at rest there is no displacement occurs in wall.
The third term upon which work done dependent is angle between force and displacement i.e Ф. If Ф=90° then W= FdcosФ= Fdcos90⇒ W=0 ( as cos 90°=0)
