Answer:
the work done by the lawnmower is 236.14 J.
Explanation:
Given;
power exerted by the lawnmower engine, P = 19 hp
time in which the power was exerted, t = 1 minute = 60 s.
1 hp = 745.7 watts
The work done by the lawnmower is calculated as follows;
Therefore, the work done by the lawnmower is 236.14 J.
The sound was repeated because of the phenomenon of echo. The speed of sound in the metal is 800 m/s.
Echo results from the reflection of sound waves. The reason why a sound may be heard twice owes to the phenomenon of reflection which leads to echo.
To determine the speed of sound in the metal;
Length of metal = 1000 m
Time taken between the two sounds = 2.5 s
Using the formula;
V = 2d/t
V = 2(1000)/2.5
V = 800 m/s
Answer:
F = 400 N
Explanation:
Given,
The acceleration of the car, a = 8 m/s²
The mass of the passenger, m = 50 Kg
The force acting on a body is equal to the product of the mass and its acceleration
F = m x a newtons
Substituting the given values in the above equation,
F = 50 Kg x 8 m/s²
= 400 N
Hence, the force exerted by the person on the seat belt is, F = 400 N
