Answer:
Is it 11.8m high or 0.6?
The question is not clear
Change in speed = (speed at the end) minus (speed at the beginning)
= (0 - 20 m/s) = -20 m/s
Acceleration = (change in speed) / (time for the change)
= (-20 m/s) / (3.5 sec) = -5.71 m/s²
Notice that this story probably didn't happen on Earth, because
the acceleration due to gravity on Earth is 9.8 m/s².
Answer:

Explanation:
Kinetic energy is given by the following equation:
, where
is mass in
and
is velocity in
.
Since the cell phone's mass is given in grams, we need to convert this into kilograms:
.
Therefore, the kinetic energy of the cell phone is:
.
Answer: -1.27 m/s^2
Explanation:
a = - V^2 / 2x
a = -(25^2) / 2 x (246) = 1.27 m/ s^2
Therefore the linear acceleration of the wheel is - 1.27 m/s^2
Answer:
Explanation:
For image formation in objective lens
object distance u = 14 +1 = 15 mm
focal length f = 14 mm .
image distance v = ?
lens formula

Putting the values

v = 210 mm .
B )
magnification = v / u
= 210 / 15
= 14
size of image = 14 x 1.1 mm
= 15.4 mm
= 15 mm approx
C )
For final image to be at infinity , image produced by objective lens must fall at the focal point of eye piece . so objective lens's distance from the image formed by objective must be equal to focal length of eye piece that is 21 mm .
21 mm is the answer .
D )
overall magnification =

D = 25 cm , f_e = focal length of eye piece
= 14 x 250 / 21
= 166.67
= 170 ( in two significant figures )