To develop this problem we will apply the concepts related to the kinematic equations of motion, specifically that of acceleration. Acceleration can be defined as the change of speed in an instant of time, mathematically this is

If a mobile is decreasing its speed (it is slowing down), then its acceleration is in the opposite direction to the movement. This would imply that the acceleration vector is opposite to the velocity vector.
Therefore the correct answer is B.
Use vector analysis and calculate resultant vector using Pythagoras theorem:
5^2 + 5^2 = 50
Square root of 50 = approx 7.1 km NE
Therefore the answer is D
Coulomb's law is express as:
Answer:
.a = 849.05 m / s²
Explanation
The centripetal acceleration is
a = v² / r
Linear and angular velocity are related
v = w r
Angular velocity and frequency are related by
w = 2π f
Let's replace
a = w² r
a = 4π² f² r
Let's reduce to the SI system
f = 2.30 rev / s (2π rad / 1 rev) = 14.45 rad / s
.r = 10.3 cm = 0.103 m
Let's calculate
a = 4π² 14.45² 0.103
.a = 849.05 m / s²
Answer:
2.068 x 10^6 m / s
Explanation:
radius, r = 5.92 x 10^-11 m
mass of electron, m = 9.1 x 10^-31 kg
charge of electron, q = 1.6 x 10^-19 C
As the electron is revolving in a circular path, it experiences a centripetal force which is balanced by the electrostatic force between the electron and the nucleus.
centripetal force = 
Electrostatic force = 
where, k be the Coulombic constant, k = 9 x 10^9 Nm^2 / C^2
So, balancing both the forces we get



v = 2.068 x 10^6 m / s
Thus, the speed of the electron is give by 2.068 x 10^6 m / s.