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
Lapatulllka [165]
3 years ago
14

21) A youngster having a mass of 50.0 kg steps off a 1.00 m high platform. If she keeps her legs fairly rigid and comes to rest

in 10.0 ms, what is her momentum just as she hits the floor? What average force acts on her during the deceleration?
Physics
1 answer:
zlopas [31]3 years ago
6 0

Answer:

-22,150 N

Explanation:

When the youngster jumps off the platform, during the fall her initial potential energy is converted into kinetic energy, according to the law of conservation of energy. Therefore, we can write:

mgh=\frac{1}{2}mu^2

where the term on the left is the potential energy while the term on the right is the kinetic energy, and where

m = 50.0 kg is the mass of the youngster

g=9.8 m/s^2 is the acceleration due to gravity

h = 1.00 m is the heigth of the platform

u is the speed of the youngster as she reaches the floor

Solving for u,

u=\sqrt{2gh}=\sqrt{2(9.8)(1.00)}=4.43 m/s

Then, when the youngster hits the floor, the force exerted on her during the deceleration is given by:

F=\frac{\Delta p}{\Delta t}=\frac{m(v-u)}{\Delta t}

where \Delta p is her change in momentum, and where

m is the mass

v = 0 is the final velocity (she comes to a stop)

u = 4.43 m/s is the initial velocity

\Delta t=10.0 ms =0.010 s is the duration of the collision

Substituting,

F=\frac{(50.0)(0-4.43)}{0.010}=-22150 N

And the negative sign means the direction of the force is opposite to the motion (so, upward).

You might be interested in
Put the waves in order from highest frequency to lowest frequency
S_A_V [24]
BCA for sure, b the lines are showing more movement
6 0
3 years ago
Read 2 more answers
At a certain location, a gravitational force with a magnitude of 350 newtons acts on a 70.-kilogram astronaut. What is the magni
creativ13 [48]

Answer:

3. 5.0N/kg

Explanation:

Gravitational field strength = gravitational force/mass of astronaut = 350N/70kg = 5.0N/kg

6 0
3 years ago
Which kind of star is most likely to spend the longest time on the main sequence?
s2008m [1.1K]
A, a low-mass red star
6 0
3 years ago
Read 2 more answers
Suppose a 4.0-kg projectile is launched vertically with a speed of 8.0 m/s. What is the maximum height the projectile reaches?
eduard

Answer:

h = 3.3 m (Look at the explanation below, please)

Explanation:

This question has to do with kinetic and potential energy. At the beginning (time of launch), there is no potential energy- we assume it starts from the ground. There, is, however, kinetic energy

Kinetic energy = \frac{1}{2}mv^{2}

Plug in the numbers = \frac{1}{2}(4.0)(8^{2})

Solve = 2(64) = 128 J

Now, since we know that the mechanical energy of a system always remains constant in the absence of outside forces (there is no outside force here), we can deduce that the kinetic energy at the bottom is equal to the potential energy at the top. Look at the diagram I have attached.

Potential energy = mgh = (4.0)(9.8)(h) = 39.2(h)

Kinetic energy = Potential Energy

128 J = 39.2h

h = 3.26 m

h= 3.3 m (because of significant figures)

7 0
2 years ago
In the 1920s what did Edmund hubble notice about the galaxies
zlopas [31]
Hubble noticed that the galaxies were moving away from us, which meant the universe was expanding.

This is why constellations change over time. In some years, the Big Dipper won't actually look like a dipper anymore.
5 0
3 years ago
Other questions:
  • Covalent compounds are usually described as
    10·1 answer
  • The two long straight wires are separated by a distance of d = 0.40 m. The currents are to the right in the upper wire and to th
    6·1 answer
  • Why are two balls connected by a spring a good model for two atoms connected by a chemical bond?
    10·1 answer
  • Type the correct answer in each box. Use numerals instead of words. If necessary, use / for the fraction bar. In a survey conduc
    14·1 answer
  • What will keep the gravitational force between two objects unchanged?
    15·1 answer
  • How much work is done by the force lifting a
    5·1 answer
  • An accumulation of different sedimentary and metamorphic rocks combined with scraps of ocean crust is called _____.
    11·2 answers
  • As I increase the frequency of a wave, what happens to the number of harmonics?
    15·1 answer
  • A problem solving method that involves trying all possible solutions until one works is using_____.
    12·1 answer
  • Where does reduction occur in an electrolytic cell
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!