Answer:
t = 25 seconds
Explanation:
Given that,
Distance, d = 115 m
Initial speed, u = 4.2 m/s
Final speed, v = 5 m/s
We need to find the time taken in increasing the speed.
We know that,
Acceleration, 
....(1)
The third equation of kinematics is as follows :
Hence, it will take 25 seconds to increase the speed.
Answer:
This process involves the motion of dislocations and is termed slip (or glide in some textbooks)
Explanation:
Plastic deformation of metals (and other crystalline materials) usually occurs by slip, which is the sliding of planes of atoms over one another by dislocation movements.
On a microscopic scale, stress causes planes of crystalline objects to leave their original position and slide over other planes into new positions, these microscopic movements manifest as a slip on a macroscopic scale. And the planes do not return back to their original position after the removal of the dislocation-causing stress.
First make sure you draw a force diagram. You should have Fn going up, Fg going down, Ff going left and another Fn going diagonally down to the right. The angle of the diagonal Fn (we'll call it Fn2) is 35° and Fn2 itself is 80N. Fn2 can be divided into two forces: Fn2x which is horizontal, and Fn2y which is vertical. Right now we only care about Fn2y.
To solve for Fn2y we use what we're given and some trig. Drawing out the actual force of Fn2 along with Fn2x and Fn2y we can see it makes a right triangle, with 80 as the hypotenuse. We want to solve for Fn2y which is the opposite side, so Sin(35)=y/80. Fn2y= 80sin35 = 45.89N
Next we solve for Fg. To do this we use Fg= 9.8 * m. Mass = 30kg, so Fg = 9.8 * 30 = 294N.
Since the chair isn't moving up or down, we can set our equation equal to zero. The net force equation in the vertical direction will be Fn + Fn2y -Fg = 0. If we plug in what we know, we get Fn + 45.89 -294 = 0. Then solve this algebraically.
Fn +45.89 -294 = 0
Fn +45.89 = 294
Fn = 248.11 N
You'll get a more accurate answer if you don't round Fn2y when solving for it, it would be something along the lines of 45.88611 etc
Answer:
Explanation:
Since the roundabout is rotating with uniform velocity ,
input power = frictional power
frictional power = 2.5 kW
frictional torque x angular velocity = 2.5 kW
frictional torque x .47 = 2.5 kW
frictional torque = 2.5 / .47 kN .m
= 5.32 kN . m
= 5 kN.m
b )
When power is switched off , it will decelerate because of frictional torque .
