Answer:
21.5°
Explanation:
Given,
Refractive index of water, n₁ = 1.33
Refractive index of polystyrene, n₂ = 1.49
Angle of reflection = ?
Angle of refraction = 19.1°
Using Snell's law
n₁ sin θ₁ = n₂ sin θ₂
1.33 x sin θ₁ = 1.49 x sin 19.1°
sin θ₁ = 0.366
θ₁ = 21.5°
According to law of reflection angle of incidence is equal to angle of reflection.
Angle of reflection = 21.5°
Answer:
The spring stretched by x = 13.7 cm
Explanation:
Given data
Mass = 3 kg
k = 120 
Angle 
= 34°
From the free body diagram
Force acting on the box = mg sin
⇒ F = 3 × 9.81 × 
⇒ F = 16.45 N ------- (1)
Since box is attached with the spring so a spring force also acts on the box.
= k x
= 120 
-------- (2)
The net force acting on the body is given by
Since acceleration of the box is zero so
Put the values from equation (1) & (2) we get
16.45 = 120
x = 0.137 m
x = 13.7 cm
Therefore the spring stretched by x = 13.7 cm
The ball took half of the total time ... 4 seconds ... to reach its highest
point, where it began to fall back down to the point of release.
At its highest point, its velocity changed from upward to downward.
At that instant, its velocity was zero.
The acceleration of gravity is 9.8 m/s². That means that an object that's
acted on only by gravity gains 9.8 m/s of downward speed every second.
-- If the object is falling downward, it moves 9.8 m/s faster every second.
-- If the object is tossed upward, it moves 9.8 m/s slower every second.
The ball took 4 seconds to lose all of its upward speed. So it must have
been thrown upward at (4 x 9.8 m/s) = 39.2 m/s .
(That's about 87.7 mph straight up. Somebody had an amazing pitching arm.)
Answer:
16000
Explanation:
Mass(m)=2Kg (1kg= 1ooo g then 2 kg=2000 g)
Velocity(v)= 4 meter
Acceleration due to gravity (g)=10m/s
We know that,
P.E= 1/2 mv^2
or, 1/2 × 2ooo × 4^2
or, 1/2×2000 ×16
or, 2000×8
Therefore= 16000
Explanation:
The machine whose efficiency is 100% is known as perfect machine .This machine is not possible in real life because every machine is affected by the overcoming friction due to which is efficiency become less than hundred percent .
