Answer: 288.8 m
Explanation:
We have the following data:
is the time it takes to the child to reach the bottom of the slope
is the initial velocity (the child started from rest)
is the angle of the slope
is the length of the slope
Now, the Force exerted on the sled along the ramp is:
(1)
Where
is the mass of the sled and
its acceleration
In addition, if we draw a free body diagram of this sled, the force along the ramp will be:
(2)
Where
is the acceleration due gravity
Then:
(3)
Finding
:
(4)
(5)
(6)
Now, we will use the following kinematic equations to find
:
(7)
(8)
Where
is the final velocity
Finding
from (7):
(9)
(10)
Substituting (10) in (8):
(11)
Finding
:

Answer:
I guess B
Explanation:
Because it stop by it self so that is digital
Heating any electrical conductor makes it's resistance INcrease.

b) Finding total distance :
Distance travelled from 0 s to 5 s :
Distance travelled from 5 s to 10 s :
Distance travelled from 10 s to 15 s :
- 150 + 1/2 x 5 x 5
- 150 + 12.5 = 162.5 m
Distance travelled from 15 s to 20 s :
- 36 x 5 + 1/2 x 5 x 4
- 180 + 10 = 190 m
Distance travelled from 20 s to 25 s :
- 45 x 5 + 1/2 x 5 x 5
- 225 + 12.5 = 237.5 m
Distance travelled from 25 s to 30 s :
- 40 x 5 + 1/2 x 10 x 5
- 200 + 25 = 225 m
Distance travelled from 30 s to 35 s :
- 20 x 5 + 1/2 x 20 x 5
- 100 + 50 = 150 m
Distance travelled from 35 s to 40 s :
Total = 75 + 150 + 162.5 + 190 + 237.5 + 225 + 150 + 50
Total = 1240 m
c) velocity at t = 15 s
d) average velocity
- 0 m/s (as displacement is equal to 0)
e) average speed
f) Part d uses displacement whereas part e uses distance