Lol, I remember I helped my sister with this question but anyways, the card flew because of inertia and the quarter fell in the glass because of gravity :).
Answer:
4 times
Explanation:
As we know that the energy of a wave is directly proportional to the square of the amplitude of the wave,
Here, the amplitude of the wave A is twice as compared to B.
So, the energy of wave A is 4 times the energy of wave B.
Speed is distance over time, learn that formula and look at the image
Answer:
The velocity of the plane at take off is 160 m/s.
The distance travel by the plane in that time is 3200 meter.
Explanation:
Given:
Acceleration, a = 4 m/s²
Time, t = 40 s
u = 0 i .e initial velocity
To Find:
velocity , v = ?
distance , s =?
Solution:
we have first Kinematic equation
v = u + at
∴ v = 0 + 4×40
∴ v = 160 m/s
Now by Third Kinematic equation

∴ s = 0 + 0.5 × 4× 40²
∴ s = 3200 meter