A kid throws a pencil straight up at
6.33 m/s. How much time does it
take for the pencil to reach
the ceiling, 1.25 m above?
(Unit = s)

Explanation:

The boy throw the pencil upward at a speed of 6.33 m/s

Then,

Initial velocity of throw is 6.33 m/s

u = 6.33 m/s.

Time to reach a maximum height of 1.25m

h = 1.25m

Note: at maximum height, the final velocity is zero

v = 0m/s

Acceleration due to gravity is

g = 9.81m/s²

We want to calculate time to reach maximum height

t = ?

Then, applying equation of motion

v = u + gt

But since it is against gravity, then, g is negaive

Then,

v = u - gt

0 = 6.33 - 9.81t

-6.33 = -9.81t

Then,

t = -6.33 / -9.81

t = 0.645 seconds

d) physical means can be used to separate the components of air.

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2