Answer:

Explanation:
As we know that average velocity is defined as the ratio of total displacement of the object and its time interval.
so here we can say

now we know that in one complete revolution the total displacement of the tip of the seconds hand is zero
because it will have same position after one complete revolution from where it starts
so here we can say that the average velocity will be zero

In order to find the our own velocity with respect to land,we need to apply the theory of relative velocity.
Now consider the velocity of the ship traveling towards the north with respect to land as A.Consider our own velocity headed northwards as B.
The relative velocity is the velocity that the body A would appear to an observer on the body B and vice versa.
In this case the relative velocity would be arrived by summing up our velocity with the velocity of the ship as the object (I) is travelling in the ship.
Relative velocity = Velocity of Body A+ Velocity of Body B.
Velocity of the ship traveling towards the north with respect to land(A)= 13.0m/s. (Given)
Our own velocity headed northwards(B)= 2.8 m/s.
Relative velocity = Velocity of Body A+ Velocity of Body B.
Relative velocity= 13.0 + 2.8 = 15.8m/s.
Thus our own velocity with respect to the land is 15.8 m/s.
Answer:

Explanation:
The Coulomb's law states that the magnitude of the electrostatic force between two charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them:

In this case, we have
:

Answer:
a) 0.05s
b) 4000N
Explanation:
a)When car is stopped its final velocity become zero
U- 10 m/s
V- 0 m/s
S - 0.25 m
t -?
S = (v+u)*t/2
0.25 =(10+0)*t/2
t = 0.05s
b) If we happened to calculate the avarage force we have to consider about acceleration
V= 0
U = 10
t = 0.05 s
a =?
V = U + at
0 = 10 -a * 0.05
a = 200 m/s2
F = m *a
= 20 * 200
= 4000N
The answer is C.
The Kinetic energy which was exerted and experience pulling the string of a bow is kept as a potential energy at the end of the arrow in contact with the string. Once release from aim at stationary position the potential energy is again transformed.