100J/20s= 5 joules per second
Or 5 watts
Answer:
B
Explanation:
i just did it on study island
The law of conservation of linear momentum says that when objects collide, the total initial momentum equals the total final momentum.
The momentum of a body is given by the product of mass and velocity of the object.
Answer:
It take 1.78033 second get away
Explanation:
We have given that a car takes 30 m to stop when its speed is 25 m/sec
As the car stops its final speed v = 0 m/sec
Initial speed u = 25 m/sec
Distance s = 30 m
From third law of motion ![v^2=u^2+2as](https://tex.z-dn.net/?f=v%5E2%3Du%5E2%2B2as)
So ![0^2=25^2+2\times a\times 30](https://tex.z-dn.net/?f=0%5E2%3D25%5E2%2B2%5Ctimes%20a%5Ctimes%2030)
![a=-10.4166m/sec^2](https://tex.z-dn.net/?f=a%3D-10.4166m%2Fsec%5E2)
Now in second case distance s = 28 m
So ![v^2=25^2+2\times -10.4166\times 28](https://tex.z-dn.net/?f=v%5E2%3D25%5E2%2B2%5Ctimes%20-10.4166%5Ctimes%2028)
![v^2=41.666](https://tex.z-dn.net/?f=v%5E2%3D41.666)
v = 6.4549 m/sec
Now from first equation of motion v=u+at
So ![6.4549=25-10.4166\times t](https://tex.z-dn.net/?f=6.4549%3D25-10.4166%5Ctimes%20t)
t = 1.78033 sec