The average speed of the car for the entire trip can be calculate by using:

where S is the total distance covered by the car, and t is the total time taken.
The total distance travelled by the car is:

while the total time taken is:

so, the average speed of the car is:

so, the correct answer is (3) 85 km/h.
The energy carried by a single photon of frequency f is given by:

where

is the Planck constant. In our problem, the frequency of the photon is

, and by using these numbers we can find the energy of the photon:
Answer:
a) 2cm³
b) 100 g/cm³
Explanation:
a- 9-7= 2cm³
b- 200 divided by 2= 100 g/cm³
Hope this helps... correct me if i'm wrong
Answer:
T²= 4π²R³/GM
Explanation:
First we know that
Fg= Fc
Because centripetal force must equal gravitational force
So
GMm/R² = Mv²/R
But velocity is 2πR/T
So by substitution we have
GMm/R²= M (2πR/T)/T
We have
T²= 4π²R³/GM as period