Haven't taken physics but I would assume if her friend is standing in front of her that you would add up the speeds and get 30 km/hr.
Answer:
A body travels 10 meters during the first 5 seconds of its travel,and a total of 30 meters over the first 10 seconds of its travel
20miles / 5sec = 4miles /sec would be the average speed for the last 20 m
Explanation:
The answer is 4 m/s.
In the first 5 seconds, a body travelled 10 meters. In the first 10 seconds of the travel, the body travelled a total of 30 meters, which means that in the last 5 seconds, it travelled 20 meters (30m + 10m).
The relation of speed (v), distance (d), and time (t) can be expressed as:
v = d/t
We need to calculate the speed of the second 5 seconds of the travel:
d = 20 m (total 30 meters - first 10 meters)
t = 5 s (time from t = 5 seconds to t = 10 seconds)
Thus:
v = 20m / 5s = 4 m/s
PLEASE GIVE BRAINIEST!! HOPE THIS HELPS
Answer:
9.34 N
Explanation:
First of all, we can calculate the speed of the wave in the string. This is given by the wave equation:

where
f is the frequency of the wave
is the wavelength
For the waves in this string we have:
, since it completes 625 cycles per second
is the wavelength
So the speed of the wave is

The speed of the waves in a string is related to the tension in the string by
(1)
where
T is the tension in the string
is the linear density
In this problem:
is the mass of the string
L = 0.75 m is the its length
Solving the equation (1) for T, we find the tension:
