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

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.

wavelength divides in half and speed stays the same.