Answer:
Vi = 32 [m/s]
Explanation:
In order to solve this problem we must use the following the two following kinematics equations.

The negative sign of the second term of the equation means that the velocity decreases, as indicated in the problem.
where:
Vf = final velocity = 8[m/s]
Vi = initial velocity [m/s]
a = acceleration = [m/s^2]
t = time = 5 [s]
Now replacing:
8 = Vi - 5*a
Vi = (8 + 5*a)
As we can see we have two unknowns the initial velocity and the acceleration, so we must use a second kinematics equation.

where:
d = distance = 100[m]
(8^2) = (8 + 5*a)^2 - (2*a*100)
64 = (64 + 80*a + 25*a^2) - 200*a
0 = 80*a - 200*a + 25*a^2
0 = - 120*a + 25*a^2
0 = 25*a(a - 4.8)
therefore:
a = 0 or a = 4.8 [m/s^2]
We choose the value of 4.8 as the acceleration value, since the zero value would not apply.
Returning to the first equation:
8 = Vi - (4.8*5)
Vi = 32 [m/s]
Answer:
a.52.9 km/h
b.90 km
Explanation:
We are given that






Time spend on eating lunch and buying ga=15 min.
a.Total time=30+12+45+15=102 minute=
1 hour=60 minutes
Distance=



Total distance=
Average speed=
Using the formula
Average speed=
b.Total distance between the initial and final city lies along the route=90 km
I think this is the answer. I hope you can understand.
The answer would be C. Gamma Rays and High Frequency EM waves travel at the speed of light and are transverse waves.