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AleksandrR [38]
3 years ago
12

Give examples of friction being useful and not useful in everyday life

Physics
2 answers:
Aloiza [94]3 years ago
6 0
If you are cold and you rub your hands together then that friction can create warmth. Useful

If you're sliding down a staircase railing and your hands are on the raiking then the friction may burn your hands a little. Not useful<span />
ruslelena [56]3 years ago
5 0
Rubbing your hands together on a cold day is an example of friction that is useful

Getting a carpet burn is an example of friction that is NOT useful
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PLS ANSWER FAST WILL GIVE BRAINLEST!!!
Kipish [7]

Answer:

2 Newtons

Explanation:

F = ma

Therefore, your mass would be 1kg and your acceleration would be 2m/s/s

Plug the numbers into the equation:

(1kg)(2m/s/s)

which will equal

2 Newtons

8 0
3 years ago
Three disks are spinning independently on the same axle without friction. Their respective rotational inertias and angular speed
ololo11 [35]

Answer:

3/7 ω

Explanation:

Initial momentum = final momentum

I(-ω) + (2I)(3ω) + (4I)(-ω/2) = (I + 2I + 4I) ωnet

-Iω + 6Iω - 2Iω = 7I ωnet

3Iω = 7I ωnet

ωnet = 3/7 ω

The final angular velocity will be 3/7 ω counterclockwise.

7 0
4 years ago
Read 2 more answers
A skateboarder is skating back and forth on the halfpipe as seen below. As he skates his energy transforms from potential energy
egoroff_w [7]

Answer:

Friction and air resistance cause some of his kinetic energy to be “lost”. This makes him slow down.

Explanation:

The law of conservation of energy states that in absence of frictional forces, the mechanical energy of an object (given by the sum of its kinetic and potential energy) is conserved. In such a situation, the skateboarder would never stop his motion, because potential energy is continuously converted into kinetic energy and vice-versa, but the total energy remains the same so he would never stop.

In a real world, however, this is not true. In fact, in a real world some frictional force are present, in particular:

- friction: this force is due to the contact between the skateboard and the surface of the halfpipe, and its direction is always opposite to the motion of the skateboarder

- Air resistance: this force is due to the resistance opposed by the molecules of air that the skateboarder meets during his motion, and its direction is also opposite to the motion of the skateboarder

This two forces are said to be non-conservative forces, which means that they cause some of the mechanical energy of the skateboarder to be "lost", in the sense that it is dissipated as heat and it is no longer available for the skateboarder.

Therefore, the correct option is

Friction and air resistance cause some of his kinetic energy to be “lost”. This makes him slow down.

7 0
4 years ago
Muốn đun sôi 200g nước từ 30 độ cần cung cấp nhiệt lượng bao nhiêu :
Aleks [24]

Answer:

cần cung cấp 70 độ vì nước sôi ở 100°C

Explanation:

7 0
3 years ago
A man starts walking north at 2 ft/s from a point p. five minutes later a woman starts walking south at 4 ft/s from a point 500
icang [17]
Refer to the diagram shown below.

After 5 minutes (300 seconds):
The man travels north by (2 ft/s)*(300 s) = 600 ft
The woman, located at q, 500 east of p, begins walking south at 4 ft/s.
The distance separating them is
d₁ = √(600² + 500²) = 781.025 ft

After 20 minutes:
The man has traveled for 20 minutes (1200 s).
The woman has traveled for 15 minutes (900 s).
The man has moved (2 ft/s)*(1200 s) = 2400 ft north of p.
The woman has moved (4 ft/s)*(900 s) = 3600 ft south of q.
The distance separating them is
d₂ = √(6000² + 500²) = 6020.8 ft

The separation from d₁ to d₂ occurs in 15 minutes (900s).
Therefore the rate of separation is
Rate = (d₂ - d₁ ft)/(900 s) = (6020.8 - 781.025)/900 = 5.822 ft/s
or
Rate = (5.822 ft/s)*(60 s/min) = 349.32 ft/min

Answer: 349.32 ft/min (or 5.82 ft/s)

4 0
3 years ago
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