Answer:
Work done by the spring is negative
Explanation:
We can answer this question by thinking what is the force acting on the box.
In fact, the force acting on the box is the restoring force of the spring, which is given by Hooke's Law:
where
k is the spring constant
x is the displacement of the box with respect to the equilibrium position of the spring
The negative sign in the equation indicates that the direction of the force is always opposite to the direction of the displacement: so, whether the spring is compressed or stretched, the force applied by the spring on the box is towards the equilibrium position.
The work done by the restoring force is also given by
where
F is the restoring force
x is the displacement
is the angle between the direction of the force and the displacement
Here we know that the force is always opposite to the displacement, so
Which means that the work done by the spring is always negative, since the direction of the restoring force is always opposite to the direction of motion.
Answer:
Explanation:
A and B are in series , Total resistance = Ra + Rb
This resistance is in parallel with single resistor C
Equivalent resistance Re = Rc x ( Ra + Rb ) / [Rc + ( Ra + Rb )]
Now this combination is in series in single resistance D .
Total resistance = Rd + Re
= Rd + { Rc x ( Ra + Rb ) / [Rc + ( Ra + Rb )] }
Answer:
(a) convex mirror
(b) virtual and magnified
(c) 23.3 cm
Explanation:
The having mirror is convex mirror.
distance of object, u = - 20 cm
magnification, m = 1.4
(a) As the image is magnified and virtual , so the mirror is convex in nature.
(b) The image is virtual and magnified.
(c) Let the distance of image is v.
Use the formula of magnification.
Use the mirror equation, let the focal length is f.
Radius of curvature, R = 2 f = 2 x 11.67 = 23.3 cm
Answer:
<em>Thermal energy</em>
Explanation:
<u>Electrical Energy
</u>
The electrical energy has been found to be an excellent resource to power our modern lifestyle. It can be produced in several ways including hydroelectrical plants, thermal plants, nuclear plants, solar panels, among many others. Each one of them converts different types of energy into electrical energy.
When converting to electrical energy, some equipment is needed, like generators, transformers, cables, circuit breakers, and every kind of devices with specific functions to have a good and safe electrical service. Each device has an internal resistance that opposes the flow of current. The resistances produce thermal energy as a result of current flowing through them. It's not possible to avoid this waste of energy, electrical engineers do their best to use better materials and configurations to reduce the thermal waste to a minimum.
