Here's the part you need to know:
(Weight of anything) =
(the thing's mass)
times
(acceleration of gravity in the place where the thing is) .
Weight = (mass ) x (gravity) .
That's always true everywhere.
You should memorize it.
For the astronaut on Saturn . . .
Weight = (mass ) x (gravity) .
Weight = (68 kg) x (10.44 m/s²)
= 709.92 newtons .
__________________________________
On Earth, gravity is only 9.8 m/s².
So as long as the astronaut is on Earth, his weight is only
(68 kg) x (9.8 m/s²)
= 666.4 newtons .
Notice that his mass is his mass ... it doesn't change
no matter where he goes.
But his weight changes in different places, because
it depends on the gravity in each place.
Answer:
3.83 m/s
Explanation:
Given that,
Distance covered by Jan, d = 4 miles
1 mile = 1609.34 m
4 miles = 6437.38 m
Time, t = 28 minutes = 1680 s
Jan's average speed,
v = d/t
Hence, the average velocity of Jan is 3.83 m/s.
Answer:
Rolling friction is much smaller than sliding friction because Rolling friction is considerably less than sliding friction as there is no work done against the body that is rolling by the force of friction. For a body to start rolling a small amount of friction is required at the point where it rests on the other surface, else it would slide instead of roll.
Rolling Friction example: Anything with weels (cars,skateboards) or a ball rooling.
Sliding Friction example: Bicycle brakes,skinning your knee walking,writing.
Answer:
Voltage-gated calcium ion channels open, and calcium ions diffuse into the cell
