Answer:
a) t = 56.34 minutes
b) v = 5.32mph
c) t = 47.22 minutes
d) v = 6.35 mph
Explanation:
Given;
The speed of Ilya and Anya are
Run = 8.90mph
Walk = 3.80mph
distance = 5.00 miles
a) anya walk half the distance and run half the distance.
Speed = distance/time
time = distance/speed
t1 = 5×0.5/3.80 = 0.658hr
t2 = 5×0.5/8.90 = 0.281hr
t = t1 + t2 = 0.658+0.281 = 0.939hr × 60minutes/hr
t = 56.34 minutes
b) average speed = total distance/total time taken
v = 5.00miles/0.939hr = 5.32mph
c) Ilya walk half the time and run half the time.
t1 = t2 = t/2
Distance = speed × time
Substituting the values.
5 = 3.80(t/2) + 8.90(t/2)
5 = 12.70(t/2)
t = 10/12.70
t = 0.787 hr × 60 minutes/hr
t = 47.22 minutes
d) average speed = 5miles/0.787hr
v = 6.35 mph
A compound machine is a combination of at least two simple machines. Simple machines can be a lever, a wedge, a while + axle, an incline plane, a pulley, and a screw.
There are many examples of compound machines. One of them is a showel that combines a wedge (the scoop part of shovel) and a lever (the handle to transfer the force to lift).
A much more complex compound machine is a bicycle, comprising simple machines ranging from wheels and axles, to screws, and levers (think of the pedals).
The neutron is uncharged. That's why it was
given a name built on "neu" from "neutral".
Time = distance / speed
Time = (4,800 meters) / (3 x 10⁸ m/s)
<em>Time = 0.000016 second</em>
This number is not one of the choices on the list. My hunch is that you copied the distance wrong.
If the estimated distance to the star is actually 4.8 x 10¹⁵ km, instead of 4.8 km, then the answer would be close to 500 years <em>(B)</em>.
There's no way a star can be "4.8 km away from the Earth". You can <em>walk</em> that far in about an hour, and passenger jet airplanes fly <em>twice</em> as far as that away from the Earth !