1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
mafiozo [28]
3 years ago
8

A balloon is rising vertically upwards at a velocity of 10m/s. When it is at a height of 45m from the ground, a parachute bails

out from it. After 3s he opens his parachute and decelerates ata a constant rate 5m/s.when.
(a) what was the height of the parachutist above the ground when he opened his parachute?
(b)How far is the parachutist from the balloon at t=3s?
(c)With what velocity does the parachutist hit the ground?
(d)After how long does the parachutist hit the ground after his exist from the balloon?
​
Physics
1 answer:
harina [27]3 years ago
8 0

(a) 30.9 m

Let's analyze the motion of the parachutist. Its vertical position above the ground is given by

y=h+ut+\frac{1}{2}gt^2

where

h = 45 m is the initial height

u = 10 m/s is the initial velocity (upward)

t is the time

g = -9.8 m/s^2 is the acceleration of gravity (downward)

Substituting t=3 s , we find the height of the parachutist when it opens the parachute:

y=45 m+(10 m/s)(3 s)+\frac{1}{2}(-9.8 m/s^2)(3 s)^2=30.9 m

(b) 44.1 m

Here we have to find first the height of the balloon 3 seconds after the parachutist has jumped off from it. The vertical position of the balloon is given by

y = h + ut

where

h = 45 m is the initial height

u = 10 m/s is the initial velocity (upward)

t is the time

Substituting t = 3 s, we find

y = 45 m + (10 m/s)(3 s) = 75 m

So the distance between the balloon and the parachutist after 3 s is

d = 75 m - 30.9 m = 44.1 m

(c) 8.2 m/s downward

The velocity of the parachutist at the moment he opens the parachute is:

v = u +gt

where

u = 10 m/s is the initial velocity (upward)

t is the time

g = -9.8 m/s^2 is the acceleration of gravity (downward)

Substituting t = 3 s,

v = 10 m/s + (-9.8 m/s^2)(3 s)= -19.4 m/s

where the negative sign means it is downward

After t=3 s, the parachutist open the parachute and it starts moving with a deceleration of

a =+5 m/s^2

where we put a positive sign since this time the acceleration is upward.

The total distance he still has to cover till the ground is

d = 30.9 m

So we can find the final velocity by using

v^2-u^2 = 2ad

where this time we have u = 19.4 m/s as initial velocity. Taking the downward direction as positive, the deceleration must be considered as negative:

a = -5 m/s^2

Solving for v,

v=\sqrt{u^2 +2ad}=\sqrt{(19.4 m/s)^2+2(-5 m/s^2)(30.9 m)}=8.2 m/s

(d) 5.24 s

We can find the duration of the second part of the motion of the parachutist (after he has opened the parachute) by using

a=\frac{v-u}{t}

where

a = -5 m/s^2 is the deceleration

v = 8.2 m/s is the final velocity

u = 19.4 m/s is the initial velocity

t is the time

Solving for t, we find

t=\frac{v-u}{a}=\frac{8.2 m/s-19.4 m/s}{-5 m/s^2}=2.24 s

And added to the 3 seconds between the instant of the jump and the moment he opens the parachute, the total time is

t = 3 s + 2.24 s = 5.24 s

You might be interested in
PLEASE HELP! How much heat is absorbed by 57g iron skillet when its temperature rises from 11°c to 30°C?
Amiraneli [1.4K]

mass times specific heat times tem change.

57 x sh x (30-11)

convert to mks and look up sh iron

7 0
3 years ago
Now set the tension to low and wiggle the wrench to create more waves. Can you explain how moving the first point on the string,
Hatshy [7]

Answer:

When the string moves, it creates a very small change in the distance to the next point, th

Explanation:

When the string moves, it creates a very small change in the distance to the next point, this generates a restoring force that tends to push the string back, this small disturbance propagates along the string and is what creates the pulse.

This is similar to what happens when a spring is stretched and a restoring force is generated shaved by the law of shortening.

            F = k Dx

4 0
2 years ago
Read 2 more answers
What force is necessary to accelerate 32kg object by 2 m/s
Oxana [17]

Answer:

i8nnndnsjdjcicicixidocin where dosoldmxbeus sosojsnnd

Explanation:

nzjwiemddsisjxnxn,jisiskxnxjxjxiisnz MN nsjs. snxjsisisis s. xjsisisk

6 0
2 years ago
A thin, light wire 75.2 cm long having a circular cross section 0.560 mm in diameter has a 25.2 kg weight attached to it, causin
blsea [12.9K]

Answer:

The stress is calculated as 1.003\times 10^{9}\ Pa

Solution:

As per the question:

Length of the wire, l = 75.2 cm = 0.752 m

Diameter of the circular cross-section, d = 0.560 mm = 0.560\times 10^{- 3}\ m

Mass of the weight attached, m = 25.2 kg

Elongation in the wire, \Delta l = 1.10\ mm = 1.10\times 10^{- 3}\ m

Now,

The stress in the wire is given by:

Stress,\ \sigma = \frac{Force,\ F}{Area,\ A}          (1)

Now,

Force is due to the weight of the attached weight:

F = mg = 25.2\times 9.8 = 246.96\ N

Cross  sectional Area, A = \pi (\frac{d}{2})^{2} = \pi (\frac{0.560\times 10^{- 3}}{2})^{2} = 2.46\times 10^{- 7}\ m^{2}

Using these values in eqn (1):

\sigma = \frac{246.96}{2.46\times 10^{- 7}} = 1.003\times 10^{9}\ Pa  

8 0
3 years ago
PLEASE SOMEONE HELP ME ILL GIVE THE PERSON BRAINLIEST
Yuliya22 [10]
I believe it would be c
5 0
3 years ago
Other questions:
  • What is the formula for a simple sugar?
    15·2 answers
  • Convert 9.2 km to m​
    6·1 answer
  • What is the formula to used to find work?
    9·1 answer
  • At 30 C, exactly 95 grams of this salt dissolved completely in 100 grams of water. According to the solubility chart, the salt i
    13·2 answers
  • How to do the equation p1v1 = p2v2 as an equation layed out like:
    7·1 answer
  • A 5.0-kg rabbit and a 12-kg Irish setter have the same kinetic energy. If the setter is running at speed 4.9 m/s, how fast is th
    7·1 answer
  • A 56.0kg ice skater spins about a vertical axis through her body with her arms horizontally outstretched, making 2.50 turns each
    5·1 answer
  • Which pairs of angles in the figure below are verticals angles ? check all that apply.
    14·1 answer
  • A car drives straight down toward the bottom of a valley and up the other side on a road whose bottom has a radius of curvature
    14·1 answer
  • Elements in Group<br> are common alkaline earth metals.<br> Answer here
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!