The first question's answer is :
If, F=ma
Then, 15N= 2.1kg (a)
15/2.1=a
7.14=a
Therefore, acceleration = 7.14m/s^2
sorry I am not sure about the second question :-(
Answer: when a circuit is completed (it allows the flow of electrons which causes the light bulb to produce light).
Explanation:
A circuit is described as an electrical setup that is consists of a light bulb, a switch, a wire, a battery which is arranged to allow the flow of electric current. The major components of the electrical circuit includes:
--> The BATTERY which is the source of voltage to the circuit,
--> the WIRE which is the conductive path,
--> the LIGHT BULB which is the load that needs electrical power to operate and
--> the SWITCH which is the controller.
When a circuit is COMPLETED when electrons can flow from one end of a battery all the way around, through the wires, to the other end of the battery. Along its way, it will carry electrons to electrical objects that are connected to it like the light bulb and make it to produce light.
There are different types of electric circuit which are designed to create a conductive path of current or electricity. They include:
--> closed circuit
--> open circuit
--> short circuit
--> parallel circuit
--> series circuit.
Answer:
work done=fdcosø
f=mg=450N
d=+3m
ø=180
450×3×cos(180°) power=work done/
time taken
1350×-1 p=135watts
Deltas are complex depositional landforms that develop at the mouths of rivers. They are composed of sediment that is deposited as a river enters a standing body of water and loses forward momentum. Famous deltas include the Mississippi delta in Louisiana and the Nile delta in Egypt.
Explanation:
(a) We have,
Length of solenoid, l = 55 cm = 0.55 m
Diameter of the solenoid, d = 10 cm
Radius, r = 5 cm = 0.05 m
Number of loops in the solenoid is 1000.
(a) The self inductance in the solenoid is given by :

A is area

(b) The energy stored in the inductor is given by :

Hence, this is the required solution.