Answer:
C)-16 N
Explanation:
concepts used
force = mass* acceleration
equation of motion

where v is the final velocity
u is the initial velocity
and s is the distance moved
______________________________________________
Given
mass = 1 kg
initial velocity (u) = 40m/s
final velocity (v) = 0 as stones comes to rest
distance moved by stone (s) = 50m
using 

Thus, acceleration is -16 m/s^2
here acceleration is negative as force of friction is opposing the motion.
Force of friction = mass of stone * acceleration of stone
Force of friction = 1*-16 kgm/s^2 = -16N ( kgm/s^2 = 1 N)
Thus, option c -16N is correct choice.
I'm afraid you're not paying attention. This question is loaded with
all the important words, and you don't recognize Newton's second
law of motion. Didn't you notice the "force", "acceleration", and
"mass" all over the place in there ?
Newton's 2nd law: Force = (mass) x (acceleration)
The answer is going to be 'mass', so let's divide
each side of Newton's law by 'acceleration':
Mass = (force) / (acceleration)
Now, just write in the numbers that the question gave you:
force = 60 newtons
acceleration = 4 m/s²
Here's the equation again: Mass = (force) / (acceleration)
= (60 N) / (4 m/s²)
= 15 kg .
1. Rainbow (white light is split into its subsequent wavelengths)
2. Light enters through the cornea, is adjusted by the lens, the cones and rods of the retina are responsible for the perception of color and shadows, which are sent through the optic nerve to the occipital lobe of the brain.
3. Sound waves are intercepted by the pinna, travels through the auditory canal, reverberates on the eardrum, the vibrations travel through the ossicles of ear (hammer, anvil and stirrup), continuing to the cochlea and are sent through the auditory nerve to the brain.
4. A medium
5. Vibrations
6. All
7. Faster
8.Their kinetic energy increases
9. Conduction, convection and radiation
10. The heating of metals in the mantle, creates a current which slowly moves the plates above it.
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