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
Vera_Pavlovna [14]
3 years ago
14

A 7.0kg skydiver is descending with a constant velocity

Physics
1 answer:
Pavel [41]3 years ago
4 0

Answer:

Air resistance: 68.6 N

Explanation:

For the skydiver falling down, there are two forces acting on him:

- The force of gravity, of magnitude

W=mg

where

m = 7.0 kg is the mass of the skydiver

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

This force acts in the downward direction

- The air resistance, R, in the upward direction

So the net force on the skydiver is:

\sum F=mg-R

According to Newton's second law of motion, the net force is also equal to mass times acceleration:

\sum F=ma

However, in this problem the skydiver is falling at constant velocity, so his acceleration is zero:

a=0

Therefore, the net force is zero:

\sum F=0

And so we can find the magnitude of the air resistance, which is equal to the weigth of the skydiver:

mg-R=0\\R=mg=(7.0)(9.8)=68.6 N

You might be interested in
What's the formula to find out power
Julli [10]

In general, 

                 Power = (energy moved) / (time to move the energy) .

If it's mechanical power, then     

                 Power = (work done) / (time to do the work) .

If it's electrical power, then it can be any one of these:

                 Power  =  (volts)  x  (amperes)

                 Power  =  (volts)²  /  (resistance, ohms)

                 Power  =  (amperes)²  x  (resistance, ohms) .

Whatever kind of energy you're dealing with, power always
turns out to be

                  (amount of energy produced, used, or moved)
divided by
                  (time taken to produce, use, or move the energy) .          
3 0
3 years ago
a snail takes 16 minutes 40 seconds to cover a distance of 1 m calculate the average speed of the swimmer​
matrenka [14]
The snail’s speed is 0.001042. Hope this helps!

8 0
2 years ago
Read 2 more answers
(a) Neil A. Armstrong was the first person to walk on the moon. The distance between the earth and the moon is . Find the time i
a_sh-v [17]

Answer:

a)<em> It took 1.28 seconds to Neil Armstrong's voice to reach the Earth via radio waves. </em>

b) <em>The minimum time that will be required for a message from Mars to reach the Earth via radio waves is 192 seconds. </em>

Explanation:

The electromagnetic spectrum is the distribution of radiation due to the different frequencies at which it radiates and its different intensitie. That radiation is formed by electromagnetic waves, which are transverse waves formed by an electric field and a magnetic field perpendicular to it.

The distribution of the radiation in the electromagnetic spectrum can also be given in wavelengths, but it is more frequent to work with it at frequencies:

  • Gamma rays
  • X-rays
  • Ultraviolet rays
  • Visible region
  • Infrared
  • Microwave
  • Radio waves.

Any radiation that belongs to electromagnetic spectrum has a speed in vacuum of 3x10^{8}m/s.  

<em>a) Find the time it took for his voice to reach the Earth via radio waves.</em>

To know the time that took for Neil Armstrong's voice to reach the Earth via radio waves, the following equation can be used:

c = \frac{d}{t}  (1)

Where v is the speed of light, d is the distance and t is the time.

Notice that t can be isolated from equation 1.

t = \frac{d}{c}  (2)

The distance from the Earth to the Moon is 3.85x10^{8} m, therefore.

t = \frac{3.85x10^{8} m}{3x10^{8}m/s}

t = 1.28s

Hence, it took 1.28 seconds to Neil Armstrong's voice to reach the Earth via radio waves.

<em>b) Determine the minimum time that will be required for a message from Mars to reach the Earth via radio waves.</em>

The distance from the Earth to the Mars at its closest approach is 5.76x10^{10}m, therefore.

t = \frac{5.76x10^{10}m}{3x10^{8}m/s}

t = 192s

Hence, the minimum time that will be required for a message from Mars to reach the Earth via radio waves is 192 seconds.

3 0
3 years ago
A combination lock has a 1.3-cm-diameter knob that is part of the dial you turn to unlock the lock. To turn that knob, you twist
galina1969 [7]

Answer:

0.04225 Nm

Explanation:

N = Force applied = 5 N

\mu = Coefficient of static friction = 0.65

d = Diameter of knob = 1.3 cm

r = Radius of knob = \frac{d}{2}=\frac{1.3}{2}=0.65\ cm

Force is given by

F=N\mu\\\Rightarrow F=5\times 0.65\\\Rightarrow F=3.25\ N

When we multiply force and radius we get torque

Torque on thumb

\tau_t=F\times r\\\Rightarrow \tau_t=3.25\times 0.0065\\\Rightarrow \tau_t=0.021125\ Nm

Torque on forefinger

\tau_f=F\times r\\\Rightarrow \tau_f=3.25\times 0.0065\\\Rightarrow \tau_f=0.021125\ Nm

The total torque is given by

\tau=\tau_t+\tau_f\\\Rightarrow \tau=0.021125+0.021125\\\Rightarrow \tau=0.04225\ Nm

The most torque that exerted on the knob is 0.04225 Nm

4 0
3 years ago
What is the difference between beta plus and minus
Minchanka [31]
Beta decay is very complex phenomena in natural radioactive decay. There are 3 types of Beta decay.

B+ decay (Beta plus or Beta positive or positron decay):

is the conversion of a proton into a neutron plus a positron and an electron neutrino.

B- decay (Beta negative or Beta nought):

is the conversion  of a neutron into a proton plus an electron and a electron antineutrino. 

Note: a positron is the a positive electron or the antiparticle of the electron.

Hope it helps
7 0
3 years ago
Other questions:
  • A force of gravity pulls downward on a book on a table. What force prevents the book from accelerating downward?
    6·2 answers
  • If you were standing at the center of curvature in front of a concave mirror, what image would be projected?
    13·1 answer
  • How are oceans connected to all bodies of water
    14·1 answer
  • H is a chemical_______and H2 is a chemical_______?
    12·1 answer
  • 3. A train has broken through the wall of a train station. During the collision, what can be said about the force exerted by the
    15·1 answer
  • A projectile of mass m is fired straight upward from the surface of an airless planet of radius R and mass M with an initial spe
    7·1 answer
  • Jackson wants to fit into last year's Halloween costume, but he has been building muscle and has gained a few healthy pounds sin
    15·1 answer
  • Score
    12·1 answer
  • Suppose a mad scientist went back in time to the beginning of the solar system and caused the newly formed Mars and Venus to swi
    6·1 answer
  • The stopping distances associated with slower speeds approximate the forward visibilities provided by low beam lights. However,
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!