The collapsed answer of Penchalreddy Badepalli is correct. The composition of two reflections via two mirror making an angle \alpha is equivalent to a single rotation by an angle 2\alpha, hence 2 * 60 deg = 120 deg. And turns is independent of the absolute orientation of the two mirrors in space and/or the direction of incidence of the incoming ray.
One could use elementary geometry to prove this (if you presume the direction of incidence is irrelevant imagine hitting the first mirror at 90 deg, then going retro right back along the normal to the first mirror, and follow the directions).
... The top branch of the 3-branched parallel block ... the 9 and 6 in series ...
is equivalent to a single resistor of 15 ohms.
... The 3-branched parallel block boils down to (30, 10, and 15) in parallel.
That's (1/30 + 1/10 + 1/15)⁻¹ = 5 ohms.
... The 5-ohm-equivalent block and the 20-ohm resistor form a
voltage divider across the battery.
The voltage across the 5-ohm-equivalent block is (5/25 x 30v) = 6v .
... The top branch of the block is equivalent to a (9 + 6) = 15-ohmer.
With 6v across its ends, the current through that branch is (6/15) = 0.4A .
... With 0.4A flowing through it, the 9-ohm resistor is dissipating
I²R = (0.4A)² (9 ohms) = (0.16 A²) (9 ohms) = 1.44 W (choice-3)
Answer:
The radius of the disc is 2.098 m.
(e) is correct option.
Explanation:
Given that,
Moment of inertia I = 12100 kg-m²
Mass of disc m = 5500 kg
Moment of inertia :
The moment of inertia is equal to the product of the mass and square of the radius.
The moment of inertia of the disc is given by
Where, m = mass of disc
r = radius of the disc
Put the value into the formula
Hence, The radius of the disc is 2.098 m.
Answer:
<h3>B. 19miles</h3>
Explanation:
If Freddy drives 4 miles east to his friend's house. He then travels 9 more miles east to the supermarket. Finally on his way back home he out of gas 6 miles after leaving the supermarket, the distance travel by fred will be the sup of all the distances he covered throughout the journey.
Distance covered by fred = 4miles + 9miles + 6miles
Distance covered by fred = 13miles + 6miles
Distance covered by fred = 19miles
