Answer:
Energy is force times distance. For your problem, no matter how long you push, the wall still goes nowhere, so there is no obvious energy transfer. so in conclusion, you actually didn't do anything :(
Explanation:
Answer:
Acceleration will be 
Explanation:
We have given initial speed of the car is 70 km/hr
We know that 1 km = 1000 m
And 1 hour = 3600 sec
So 
It is given that car stops in 12 sec
So final speed of the car v = 0 m/sec
Time t = 12 sec
From first equation of motion v = u+at
So 
( negative sign indicates that speed of the car will constantly decrease )
when the apple moves in a horizontal circle, the tension force in the string provides the necessary centripetal force to move in circle. the tension in the string is given as
T=mv²/r
where T = tension force in the string , m = mass of the apple
v = speed of apple , r = radius of circle.
clearly , tension force depends on the square of the speed. hence greater the speed, greater will be the tension force.
at some point , the speed becomes large enough that it makes the tension force in the string becomes greater than the tensile strength of the string. at that point , the string breaks
Answer:
a)
b)
c)
d)
e)
Explanation:
Given that:
- initial speed of turntable,

- full speed of rotation,

- time taken to reach full speed from rest,

- final speed after the change,

- no. of revolutions made to reach the new final speed,

(a)
∵ 1 rev = 2π radians
∴ angular speed ω:

where N = angular speed in rpm.
putting the respective values from case 1 we've


(c)
using the equation of motion:

here α is the angular acceleration



(b)
using the equation of motion:





(d)
using equation of motion:



(e)
using the equation of motion:


