Answer:
Explanation:
Given
mass of boy 
mass of girl 
speed of girl after push 
Suppose speed of boy after push is 
initially momentum of system is zero so final momentum is also zero because momentum is conserved




i.e. velocity of boy is 2.82 m/s towards west
Answer:
Final Speed of Dwayne 'The Rock' Johnson = 15.812 m/s
Explanation:
Let's start out with finding the force acting downwards because of the mass of 'The Rock':
Dwayne 'The Rock' Johnson: 118kg x 9.81m/s = 1157.58 N
Now the problem also states that the kinetic friction of the desk in this problem is 370 N
Since the pulley is smooth, the weight of Dwayne Johnson being transferred fully, and pulls the desk with a force of 1157.58 N. The frictional force of the desk is resisting this motion by a force of 370 N. Subtracting both forces we get the resultant force on the desk to be: 1157.58 - 370 = 787.58 N
Now lets use F = ma to calculate for the acceleration of the desk:
787.58 = 63 x acceleration
acceleration = 12.501 m/s
Finally, we can use the motion equation:

here u = 0 m/s (since initial speed of the desk is 0)
a = 12.501 m/s
and s = 10 m
Solving this we get:


Since the desk and Mr. Dwayne Johnson are connected by a taught rope, they are travelling at the same speed. Thus, Dwayne also travels at 15.812 m/s when the desk reaches the window.
Answer:
False
Explanation:
As we know that, the Balmer series gives the n values as,
.
.
Now the value of wavelength can be calculated as,
.
Here,
.
And
.
Now,
.
Therefore,

Therefore, the wavelength of Balmer series lies in visible region which is 547 nm.
Answer:
-8.56V
Explanation:
Our values are given by,
e = 6.04 V
Φ = 30.3
VC = 5.32
We can calculate the voltage across the circuit with the emf formula, that is,




Now, Using Kirchoff Voltage Law,


Finally we have the potential difference across the inductor.

Answer:
a). 53.75 N and 101.92 N
b). 381.44 N and 723.25 N
Explanation:

a).
ρ
,
, 

b).
ρ
,
, 
