Hii please help i’ll give brainliest if you give a correct answer please

A rock is dropped from the top of a tall building. The rock's displacement in the last second before it hits the ground is 46 %

olasank [31]

Answer:

height is 69.68 m

Explanation:

given data

before it hits the ground = 46 % of entire distance

to find out

the height

solution

we know here acceleration and displacement that is

d = (0.5)gt² ..............1

here d is distance and g is acceleration and t is time

so when object falling it will be

h = 4.9 t² ....................2

and in 1st part of question

we have (100% - 46% ) = 54 %

so falling objects will be there

0.54 h = 4.9 (t-1)² ...................3

so

now we have 2 equation with unknown

we equate both equation

1st equation already solve for h

substitute h in the second equation and find t

0.54 × 4.9 t² = 4.9 (t-1)²

t = 0.576 s and 3.771 s

we use here 3.771 s because 0.576 s is useless displacement in the last second before it hits the ground is 46 % of the entire distance it falls

so take t = 3.771 s

then h from equation 2

h = 4.9 t²

h = 4.9 (3.771)²

h = 69.68 m

so height is 69.68 m

6 0

4 years ago

A ball is thrown up at 30m/s from the ground. What is it s maximum height? How long did it take?

Rzqust [24]

Answer:

Maximum height reached by the ball thrown up at 30m/s is 3.06 seconds and the height reached is 45.9 meters

Explanation:

Given:

Initial velocity $u=30 \mathrm{m} / \mathrm{s}$

To find :

maximum height =?

time taken=?

Solution:

Step 1:Finding the time taken to reach the highest point:

The velocity of the ball at its highest ,final velocity v=0

Using the formula,

$v=u+a t$

Where a is acceleration due to gravity.Its value is $-9.8 m / s^{2}$

Substituting the values:

$0=30+(-9.8) t$

$-30=(-9.8) t$

$t=\frac{30}{9.8}$

$t=3.06 \mathrm{seconds}$

Step 2: finding the highest point

Using the formula

$v^{2}-u^{2}=2 a s$

where

s is the maximum highest.

Substituting values

$0^{2}-(30)^{2}=2(-9.8) s$

$0-900=(-19.6) s$

$-900=(-19.6) s$

$s=\frac{900}{19.6}$

$s=45.9 \text { meters }$

Result:

Thus the maximum height reached is 45.9 meters in 3.06 seconds

3 0

3 years ago

Read 2 more answers

-Cesar the monkey observed the swinging behaviors of his parents. He is now able to swing from branch to branch after much pract

alexgriva [62]

The 3rd one I think . I did something similar a while ago

4 0

3 years ago

Two processes of plant reproduction are described below.

alex41 [277]

Answer:

Process 1

Explanation:

Bees help move the pollen from flower to flower

5 0

3 years ago

Read 2 more answers

A spring has a constant k= 10.32 N/m and is hung vertically. A 0.400kg mass is suspended from the spring. What is the displaceme

alukav5142 [94]

Answer:

displacement (x) = 0.003798 meters

Explanation:

from the fact that the string is hung vertically we can deduce that:

Total force acting on the mass = Fs (by spring) + Fg (by gravity)

where

Fs = k*x , x is the displacement..

Fg = m*g

then:

Ftot = m*a, but a = 0 m/(s^2) because the mass becames stationary.

Ftot = 0

Fs + Fg = 0

by direction, take down as negative.

Fs - Fg = 0

k*x = m*g

x = m*g/k = [(0.400)(9.8)]/(10.32)

= 0.3798 meters

4 0

3 years ago