Explanation:
1. Distance, d = 5 m
Time, t = 10 s
Speed = distance/time
2. Mass, m = 10 kg
Acceleration, a = 3 m/s³
Force, F = mass (m) × acceleration (a)
F = 10 × 3
= 20 N
3. Mass, m = 7 kg
Height, h = 4 m
Potential energy, E = mgh
E = 7 × 9.8 × 4
E = 274.4 J
Hence, this is the required solution.
Answer:The frequency of the echo is slightly decreased
Explanation:
Given
speed of boat
cliff is away
when boat is still , suppose t is the time taken by the echo to reach observer on the boat
But as soon as boat starts moving the distance between cliff and boat decreasing and time for echo to reach observer also decreases
and we know
therefore frequency of the echo slightly decreased.