Answer:
The correct choice is D. Concentric exercise can be hard on joints, so she should be very careful.
Answer:
Electric field at a point ( x , y , z) is
.
Explanation:
Given :
Electric potential in the region is , 
We need to find the electric field .
We know , electric field ,
{ Here r is distance }
In coordinate system ,
{
is partial derivative }
Putting all values we get ,

Hence , this is the required solution.
Answer:
a = 15.1 g
Explanation:
The relation between mass and acceleration is given by :

If a₁ = 0.80g, m₁ = 1510 kg, m₂ = 80 kg, we need to find a₂
So,

So, the car's acceleration would be 15.1 g.
Answer:

Explanation:
We should first find the velocity and acceleration functions. The velocity function is the derivative of the position function with respect to time, and the acceleration function is the derivative of the velocity function with respect to time.

Similarly,

Now, the angle between velocity and acceleration vectors can be found.
The angle between any two vectors can be found by scalar product of them:

So,

At time t = 0, this equation becomes
