_____ are group of tissue working together to perform a certain job.

You lift a 45-newton bag of mulch 1.2 meters and carry it a distance of 10 meters to the garden. How much

zysi [14]

To lift the bag straight up takes (F · D) = (45 · 1.2) = 54 joules of energy (work).

Moving the bag horizontally 'across' gravity requires no work.
It doesn't matter how far.

4 0

4 years ago

Determined to test the law of gravity for himself, a student walks off a skyscraper 180 m high, stopwatch in hand, and starts hi

Sati [7]

Answer:

a) v₀ = - 164.62 m / s , c) y = 122.5 m

Explanation:

We can solve this exercise using the free fall kinematic relations.

We put our reference system on the floor, so the height of the skyscraper is y₀ = 180m and the floor level is y = 0 m

For the boy

y = y₀ + v₀ t - ½ g t²

with free fall its initial speed is zero

y = ½ g t2

For superman

y = y₀ + v₀ (t-5) - ½ g (t-5)²

how superman grabs the lot just before hitting the ground

we look for the time it takes the boy down

t = √ (2 y₀ / g)

t = √ (2 180 / 9,8)

t = 6.06 s

in the equation for superman, we clear the volume and calculate

v₀ (t-5) = -y₀ + ½ g (t-5)²

v₀ (6.06 -5) = -180 + ½ 9.8 (6.06 -5)²

v₀ 1.06 = -174.49

v₀ = - 174.49 / 1.06

v₀ = - 164.62 m / s

the negative sign indicates that the initial speed is down

b) to graph the position of the two we use the table

t (s) Y_boy (m) Y_superman (m)

0 180 180

1 175.1 180

5 57.5 180

6 3.6 10.18

see attachment for the two curves

c) calculate the height that falls a lot in the 5 seconds (t = 5)

y = -1/2 g t²

y = ½ 9.8 5²

y = 122.5 m

for this height superman has not yet left the skyscraper, so the boy hits the ground

8 0

4 years ago

You punt a ball straight up at 20 m/s. What is the balls hangtime

Natalija [7]

The hang time of the ball is 4.08 s

Explanation:

The ball is in free fall motion: this means that it is acted upon gravity only, so its acceleration is the acceleration of gravity,

$a=g=-9.8 m/s^2$

downward (the negative sign refers to the downward direction).

Since this is a uniformly accelerated motion, we can solve the problem by using the following suvat equation:

$v=u+at$

where

v is the final velocity

u is the initial velocity

a is the acceleration

t is the time

First we calculate the time it takes for the ball to reach the maximum height, where the velocity is zero:

v = 0

Substituting:

u = +20 m/s

$a=-9.8 m/s^2$

we find t

$t=\frac{v-u}{a}=\frac{0-20}{-9.8}=2.04 s$

The motion of the ball is symmetrical, so the total time of flight is just twice the time needed to reach the maximum height, therefore:

$T=2t=2(2.04)=4.08 s$

Learn more about free fall:

brainly.com/question/1748290

brainly.com/question/11042118

brainly.com/question/2455974

brainly.com/question/2607086

#LearnwithBrainly

4 0

3 years ago

Time-outs are ineffective because

maria [59]

I think the correct answer would be the child quietly sits until the timer goes off. It is ineffective because the child would be used to this process and would come to a time where he will not get something from it.Also, it would make a child feel isolated and alone which would affect hi self-esteem in a long run.

8 0

3 years ago

Read 2 more answers

a sailboat sails 50 km to the north then 80 km in the direction 38 degrees west of south. what is the net displacement of the bo

True [87]

Answer:

35.489km

Explanation:

a diagram illustrating the question is attached

now, applying cosine rule to find the displacement c

cosine rule;

c²=a²+b²-2abCos ∅