Answer:
Explanation:
Assume that the distance travelled initially is d.
In order to stop the block you need some external force which is friction.
If we use the law of energy conservation:
a)
Looking at the formula you can see that the mass doesn't affect the distance travelled, as lng as the initial velocity is constant (Which indicates that the force must be higher to push the block to the same speed) therefore the distance is the same.
b) If the velocity is doubled, then the distance travelled is multiplied by 4, because the distance deppends on the square of the velocity.
The first one is right switch the second and third one and keep the last one and that should be right
Speed is given as distance divided by time. I think that first you should simplify the two rates 58/2=29km/hr and 71/4=17.75km/hr After that find the mean or average which is (29+17.75)/2=23.375km/hr
Therefore it is safe to say that the average speed of the train is 23.375km/hr. I am not sure about this.
Answer:
Work Done= 3150J
Power= 1.75W
Explanation:
Work Done= Force x the distance travelled in the direction of the force (W= f x d)
Weight is a force, i think the qn. stated it wrongly, it should be 70N not 70kg.
Work Done= 70 x 45
=3150J
Power= Work Done/Time
=3150/(30x60)
*convert minutes to seconds since the S.I. unit of Power is joules/seconds(J/s) or watts(W)
=1.75W
