Explanation:
(4566 m / 4 min) × (1 km / 1000 m) × (60 min / h) = 68.49 km/h
No, because the distance-time would show a constant velocity but the velocity-time graph shows an increasing velocity.
Answer:

Explanation:
The gravitational potential energy gets transformed into translational and rotational kinetic energy, so we can write
. Since
(the ball rolls without slipping) and for a solid sphere
, we have:

So our translational speed will be:

Answer:
Conservation of momentum - causes a recoil of cannon frame after launch
Explanation:
- It is simple, we can apply the conservation of momentum on the system. Initial momentum P_i before shooting is zero. Then after you strike the cannon up, the ball will go to the target however for the momentum to be conserved the cannon frame must move backwards with the same momentum with which the cannon ball is launched.
Hence, the recoil of the cannon frame would be large enough to dislodge you off the ground and throw you a few feet back.
Answer:
The phase change of
can be theoretically understood as follows:
For transmission or propagation of waves between media the wave motion should maintain a principle of continuity meaning that the wave function at the interface should be continuous and diffrentiable at the interface.
At the point of incidence there are 2 types of waves reflected wave and the incident wave. Now the principle of continuity dictates that the sum of the phases of the above 2 waves should be same as that of transmitted wave. If we use these relations we notice that the reflected wave shall either change it's phase by
or will not change it's phase depending on the relationship between the refractive indices of the incident and the reflecting medium. For a solid boundary a phase change of
occurs.