Answer:


The motion of the block is downwards with acceleration 1.7 m/s^2.
Explanation:
First, we will calculate the acceleration using the kinematics equations. We will denote the direction along the incline as x-direction.

Newton’s Second Law can be used to find the net force applied on the block in the -x-direction.

Now, let’s investigate the free-body diagram of the block.
Along the x-direction, there are two forces: The x-component of the block’s weight and the kinetic friction force. Therefore,

As for the static friction, we will consider the angle 31.8, but just before the block starts the move.

Answer:
15 watt
Explanation:
Power is the rate at which work is done.
This means you divide the work done with the amount of time used to perform the work.
The formula for Power is : P = W/t where;
W= work done in J = 45
t= time in seconds = 3 sec
P= 45/ 3 = 15 watt
Answer:
Density of 127 I = 
Also, 
Explanation:
Given, the radius of a nucleus is given as
.
where,
- A is the mass number of the nucleus.
The density of the nucleus is defined as the mass of the nucleus M per unit volume V.

For the nucleus 127 I,
Mass, M = 
Mass number, A = 127.
Therefore, the density of the 127 I nucleus is given by

On comparing with the density of the solid iodine,

It probably is the actual answer.