Open with Part 2. Problem Solving

Directions: Follow the GUESS Method of solving problem to get full credit for your works

1. A kid throws a rock off the edge of a cliff 60.0 m high. When he drops the rock, it takes 5,0

sec for it to reach the ground below.

a.) Determine the time it takes to reach the ground below, and

b.) How long would it take the rock to hit the ground if he threw it down with a speed of 15

m/sec?

is hit stmight upward and reach a maximum height of 80.0 m.

A.) 5s

B.) 2.29s

C.) 39.6 m/s

Explanation:

Given that a kid throws a rock off the edge of a cliff 60.0 m high. When he drops the rock, it takes 5,0sec for it to reach the ground below.

a.) Determine the time it takes to reach the ground below,

The time is 5s

b.) How long would it take the rock to hit the ground if he threw it down with a speed of 15m/sec?

Using the second equation of motion:

H = Ut + 1/2gt^2

Substitute all the parameters into the formula

60 = 15t + 1/2 × 9.8 × t^2

60 = 15t + 4.9t^2

Multiply all by 10

49t^2 + 150t - 600

t^2 + 3.06t = 12.24

( t + 1.53)^2 = 12.24 + 2.3409

t + 1.53 = sqrt ( 14.5809)

t = 3.82 - 1.53

t = 2.29s

is hit stmight upward and reach a maximum height of 80.0 m.

Using the third equation of motion

V^2 = U^2 - 2gH

At maximum height, V = 0

0 = U^2 - 2 × 9.8 × 80

U^2 = 1568

U = sqrt ( 1568)

U = 39.6 m/s

answer: (431,2)

step-by-step explanation: