Answer:
22km/h
Explanation:
The speed of the keys relative to the ground will be given by the sum of speed of keys with respect to the ground and the speed of keys with respect to the skater
Given that the speed of keys with respect to the ground is 8 m/s while the speed of keys with respect to skater is 14 km/h then the relative speed which combines both speeds will be 8+14=22 km/hr
Yes, for example a plain is moving so it has kinetic energy, it is also high above the ground so it has gravitational potential energy
Answer:
(1) V = 0.2 J (2) 0.05J
Explanation:
Solution
Given that:
K = 160 N/m
x = 0.05 m
Now,
(1) we solve for the initial potential energy stored
Thus,
V = 1/2 kx² = 0.5 * 160 * (0.05)²
Therefore V = 0.2 J
(2)Now, we solve for how much of the internal energy is produced as the toy springs up to its maximum height.
By using the energy conversion, we have the following
ΔV = mgh
=(0.1/9.8) * 9.8 * 1.5 = 0.15J
The internal energy = 0.2 -0.15
=0.05J
Answer:
Its focal length is positive
Explanation:
A concave mirror is shown in attached figure. The distance from the pole to the focus of the mirror is called its focal length. Spherical mirrors are a part of a sphere.
As per conventions, we know that the axis opposite to x axis is taken as negative.
So, it is clear that the focal length of spherical concave mirror is negative.
Hence, the incorrect option is (c) " its focal length is positive".
Answer:
Explanation:
Let the velocity of lander with respect to earth be v .
In relativistic mechanism the expression for relative velocity is
v_r = 
Given u = .6c , v_r = .8 c
Substituting the values
.8c = 
.8c-.48v = v - .6c
v = .946c
b )
Distance in terms of time = .2 ly
In relativistic mechanism , expression for relativistic time is given by the following relation
t = 
Substituting v = .946c
t₀ = .2
t = 
.2 / √.1050
= .62 ly
distance to the Earth at the time of lander launch, as observed by the aliens will be .62 ly.