Answer:
<u>Principal</u><u> </u><u>focus</u><u> </u><u>of</u><u> </u><u>concav</u><u>e</u><u> </u><u>lens</u><u> </u><u>-</u><u> </u>
★ The point at which rays parallel to principal axis coming from infinity appear to converge after being refracted from concave lens is called the principal focus of concave lens.
<em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em><em><u>_</u></em>
• <u>Additional</u><u> information</u><u> </u><u>-</u><u> </u>
★ Principal focus - A number of rays parallel to the principal axis after reflection from a concave mirror meet at a point on the principal axis or appear to come from a point after reflection from a convex mirror on the principal axis. This is called principal focus.
Answer:
(a) 0.942 m
(b) 18.84 m/s
(c) 2366.3 m/s²
(d) 0.05 s
Explanation:
(a) In one revolution, it travels through one circumference, 2πr = 2 × 3.14 × 0.15 m = 0.942 m.
(b) Its frequency, f, is 1200 rev/min =
rev/s = 20 rev/s.
Its angular frequency, ω = 2πf = 2π × 20 = 40π
The speed is given by
v = ωr = 40π × 0.15 = 6π = 18.84 m/s
(c) Its acceleration is given by, a = ω²r = (40π)² × 0.15 = 2366.3 m/s²
(d) The period is the inverse of the frequency because it is the time taken to complete one revolution.

T = 1/20 = 0.05 s
Answer:
27 m/s
will be the new velocity
Explanation:
if acceleration is 3 then it must be 3 m/s^2
As per Newton's II law we know that

here
F = applied unbalanced force
m = mass of object
a = acceleration of object
now it is given that force F = 50 N North applied on block on earth due to which block will accelerate by 4 m/s^2
so here from above equation


Now we took another situation where block is placed on surface of moon and again force F = 25 N is applied on the block
So we will again use Newton's II law




so block will accelerate on moon by acceleration 2 m/s^2
The units used to measure specific heat capacity is Joules per kilogram per Kelvin.
<h3>What is specific heat capacity?</h3>
It is the amount of heat absorbed per kilogram of material when the temperature rises by 1 kelvin.
Specific heat capacity C is the Joules of energy in form of heat per kilogram per Kelvin temperature. The units represented by
C = ___ J/kg.K
Thus, the units used to measure specific heat capacity is Joules per kilogram per Kelvin.
Learn more about specific heat capacity.
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