Answer:
The wave speed is calculated below:
Explanation:
Given,
number of waves passed per minute = 8
time period = 1 minute = 60 s
distance between successive wave crests = 20 m
waves passing interval per second =

Now,
wave speed = 20 m ×

=
m/s
= 2.67 m/s
Hence the wave speed is 2.67 m/s.
Answer:
From the second law of motion:
F = ma
we are given that the force applied on the block is 20N and the block accelerates at an acceleration of 4 m/s/s
So, F= 20N and a = 4 m/s/s
Replacing the variables in the equation:
20 = 4* m
m = 20 / 4
m = 5 kg
Answer:

Explanation:
We can solve this problem by using Newton's second law of motion, which states that the net force acting on an object is equal to the product between its mass and its acceleration:

where
F is the net force on the object
m is its mass
a is its acceleration
In this problem:
F = 40 N is the force on the object
m = 2 kg is its mass
Therefore, the acceleration of the object is

The velocity of the combination of Jackie and the bicycle is 3.328 m/s.
Explanation:
From the given data the constant kinetic energy is 3.6 J. The mass of combination is 0.65 kg. To find the velocity of the combination of Jackie and the bicycle the formula is
KE = 0.5 x mv2.
To find velocity,
V2=ke/(0.5×m)
V=
v= 3.6/(0.5×0.65)
=
v= 3.328 m/s
Hence, the velocity of the combination of Jackie and the bicycle is 3.328m/s.