Work done is given by product of force and displacement due to that force
So here we will have

here we know that


Now work done is given as


so it will do 16 J work to move the box
Answer:
a. 
b.
must be the minimum magnitude of deceleration to avoid hitting the leading car before stopping
c.
is the time taken to stop after braking
Explanation:
Given:
- speed of leading car,

- speed of lagging car,

- distance between the cars,

- deceleration of the leading car after braking,

a.
Time taken by the car to stop:

where:
, final velocity after braking
time taken


b.
using the eq. of motion for the given condition:

where:
final velocity of the chasing car after braking = 0
acceleration of the chasing car after braking

must be the minimum magnitude of deceleration to avoid hitting the leading car before stopping
c.
time taken by the chasing car to stop:


is the time taken to stop after braking
Specific heat. The definition of specific heat is the amount of energy required to raise the temperature of 1g of a substance by 1K or 1°C.
Answer:
1) In a concave mirror parallel rays falling on it converges at F and 2F.
Explanation:
Spherical mirrors can be used for magnification of images. There are basically two types of spherical mirrors and they are converging mirror and diverging mirrors. The converging mirrors are also termed as concave mirrors and its basic work is to converge or combine light rays coming from a larger distance to a single point. Mostly the light beams falling parallel to the principle axis of the concave mirror will be acting as parallel rays. And when these parallel rays fall on the mirror, the converging point can be the focal point of the mirror.
Thus the location of converging point in concave mirrors will be based on the position or distance of object from the mirror. If the object distance is very far from the twice the focal length distance of mirror, then the converging point will be the focal point or F. And if the object is placed slightly greater than twice the distance of focal point, then the image will be obtained at 2F. But the parallel beams will be converging at F and 2F.
The best answer is b) increased turbidity from erosion.
Nonpoint source pollution generally happens as a result of many systems interacting, and is not directly attributed to one event or pollutant. Generally, natural environmental systems participate in pollution of this kind, regardless of whether or not human activity was a factor. Examples include water runoff, or erosion.
The other pollutants listed have a direct cause and direct effect, the animal waste goes directly from the animals to the ground they live on, the car shop directly sumps the oil on the ground, and the oil tank leaks directly into the earth. Erosion causing turbidity is a less direct form of pollution, and is due to the synthesis of several natural phenomena<span />