Answer:
400 J
Explanation:
Work is done when a force that is applied to an object moves that object.
The work is calculated by multiplying the force by the amount of movement of an object
W = F * d
here the man has to work against the gravitational field. (against his weight)
F =100 N
Work done = F * d
= 100 * 4
= 400 J
Answer:
The final speed of puck 1 is 0.739 m/s towards west and puck 2 is 2.02 m/s towards east .
Explanation:
Let us consider east as positive direction and west as negative direction .
Given
mass of puck 1 , 
mass of puck 2 , 
initial speed of puck 1 , 
initial speed of puck 2 , 
Final speed of puck 1 and puck 2 be 
respectively
Apply conservation of linear momentum
=>
=>
-----(A)
Since collision is perfectly elastic , coefficient restitution e=1
=>
------(B)
From equation (A) and (B)
and 
Thus the final speed of puck 1 is 0.739 m/s towards west and puck 2 is 2.02 m/s towards east .
Answer:
The 2 light bulbs can be connected in parallel to each other to avoid disconnection when one bulb burns out.
Explanation:
The parallel connection is required not series. A parallel connection is the connection of electronic components (e.g bulbs, LED, resistors, capacitors etc) in such a way that the same voltage is supplied across the ends of the components. While in a series connection, the components are connected to each other end-to-end.
As regard the question, parallel connection ensures that the brightness any of the bulbs is not affected with respect to the other bulbs. And other bulbs continue to function when any burns out. The 2 light bulbs should be connected in parallel to the baterry to avoid disconnection of all the bulbs.
