Answer:
(a) 7.72×10⁵ J
(b) 4000 J
(c) 1.82×10⁻¹⁶ J
Explanation:
Kinetic Energy: This can be defined energy of a body due to its motion. The expression for kinetic energy is given as,
Ek = 1/2mv²................... Equation 1
Where Ek = Kinetic energy, m = mass, v = velocity
(a)
For a moving automobile,
Ek = 1/2mv².
Given: m = 2.0×10³ kg, v = 100 km/h = 100(1000/3600) m/s = 27.78 m/s
Substitute into equation 1
Ek = 1/2(2.0×10³)(27.78²)
Ek = 7.72×10⁵ J
(b)
For a sprinting runner,
Given: m = 80 kg, v = 10 m/s
Substitute into equation 1 above,
Ek = 1/2(80)(10²)
Ek = 40(100)
Ek = 4000 J
(c)
For a moving electron,
Given: m = 9.10×10⁻³¹ kg, v = 2.0×10⁷ m/s
Substitute into equation 1 above,
Ek = 1/2(9.10×10⁻³¹)(2.0×10⁷)²
Ek = 1.82×10⁻¹⁶ J
Answer:
s^ -1 ( or 1/sec)
Explanation:
Velocity is given in units of displacement / sec
like feet /sec or m/sec
so b would have units of s^-1
(or perhaps a more general term would be time^-1)
It's weird but technically correct to say that a radio wave can be considered a low-frequency light wave. Radio and light are both electromagnetic waves. The only difference is that radio waves have much much much longer wavelengths, and much much much lower frequencies, than light waves have. But they're both the same physical phenomenon.
However, a radio wave CAN'T also be considered to be a sound wave. These two things are as different as two waves can be.
-- Radio is an electromagnetic wave. Sound is a mechanical wave.
-- Radio waves travel more than 800 thousand times faster than sound waves do.
-- Radio waves are transverse waves. Sound waves are longitudinal waves.
-- Radio waves can travel through empty space. Sound waves need material stuff to travel through.
-- Radio waves can be detected by radio, TV, and microwave receivers. Sound waves can't.
-- Sound waves can be detected by our ears. Radio waves can't.
-- Sound waves can be generated by talking, or by hitting a frying pan with a spoon. Radio waves can't.
-- Radio waves can be generated by an alternating current flowing through an isolated wire. Sound waves can't.
the formula for momentum is velocity times mass
car :
1200 x 30 = 36000
truck:
2000 x 20 = 40000
Ans : truck has a greater momentum
