Answer:
45km/hr
Explanation:
Total distance=450km
Total speed=50km/hr
Total time= distance/speed
=450/50
=9hrs
distance a=180km
speed a=60km/hr
Time a=180/60
=3hrs
Distance b=450-180=270km
Speed b=?
Time b=270/speed b
Total time=time a + time b
9=3+(270/speed b)
270/speed b =9-3
270/speed b =6
6*speed b =270
Speed b=270/6
Speed b=45km/hr
<h2>The hiker will go up to 850 m on the hill</h2>
Explanation:
The total energy gained by the hiker = 140 x 4186 J
This energy is consumed in the potential energy acquired , while climbing up the hill.
The potential energy P.E = mass of hiker x acceleration due to gravity x height
Thus
140 x 4186 = 69 x 10 x h
or h =
= 850 m
If the 20% of the total energy is used
the height h₀ =
= 170 m
Answer:
a. 
b. 
Explanation:
The inertia can be find using
a.





now to find the torsion constant can use knowing the period of the balance
b.
T=0.5 s

Solve to K'


The index of refraction of a material is the ratio between the speed of light in vacuum, c, and the speed of light in that material, v:

where the speed of light in vacuum is

. The speed of light in benzene is

, so we can use the previous relationship to find the refractive index of benzene:
You can write an hypothesis such as this:
The weight of an object has effects on the operating frictional force, the greater the weight, the higher the operating frictional force.
The father is the one with the higher weight while the son has the lower weight. The operating frictional force is the friction that their weights exert.