Answer:
1.0 dioptres
Explanation:
Farsightedness is an eye defect in which a person can see far objects clearly but not near objects. That implies that the patients' near point is farther than 25cm which is the normal least distance of distinct vision.
Farsightedness results from the eyeball being too long or the crystalline lens not being sufficiently converging.
Carol is farsighted with a near point of about a meter (100cm). We desire to make a lens to enable her near point be reduced to about 50cm. The focal length and power of this lens is calculated in the image attached.
The power of a lens is the inverse of its focal length in meters hence the 100 in the formula for power of the lens.
Answer: The elevator must be accelerating.
Explanation:
As the tension force is opposing to the the force of gravity on the load which is hung vertically, and the tension force can adopt any value in order to comply with Newton's 2nd law, if the tension force is less than the force due to gravity, this means that all system is not in equilibrium, so it must be accelerating.
If we assume that the downward is the positive direction, we can write:
mg - T = ma
If T = 0.9 mg, ⇒ mg (1-0.9) =0.1 mg = m a ⇒a = 0.1 g , in downward direction.
Answer:
7560 Joules
Explanation:
= Mass of first car = 
= Mass of second car = 
= Initial Velocity of first car = 0.3 m/s
= Initial Velocity of second car = -0.12 m/s
v = Velocity of combined mass
As linear momentum of the system is conserved
Energy lost is
The Energy lost in the collision is 7560 Joules
Explanation:
tilting it will raise the height of its center of gravity.
I know it, X-rays<span>, </span>gamma rays<span> and beta particles are all </span>used<span> in medicine to treat internal organs. X-</span>rays<span> are produced by firing electrons at a metal target and </span>gamma rays<span> are emitted by the nucleus of radioactive atoms. </span>Gamma rays<span> are </span>used<span> to kill cancer cells, to sterilise medical equipment and in radioactive tracers.</span>
