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Feliz [49]
3 years ago
7

A 1,200 kg car rolls down a hill with its brakes off and transmission in neutral. At one moment it is moving 5.0 m/s. A little l

ater it is moving at 8.2 m/s. How much did its height change between the two times? Assume friction and air resistance have no effect on its motion.
Physics
1 answer:
Y_Kistochka [10]3 years ago
4 0
The change in kinetic energy of the car is equivalent to the change in its potential energy. Thus:
K.E  = P.E
1/2 x mΔv² = mgΔh
h = (8.2² - 5²) / 2(9.81)
h = 2.15 meters
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A hockey puck is sliding across a frozen pond with an initial speed of 9.3 m/s. It comes to rest after sliding a distance of 42.
kondaur [170]

Answer:

The coefficient of kinetic friction between the puck and the ice is 0.11

Explanation:

Given;

initial speed, u = 9.3 m/s

sliding distance, S = 42 m

From equation of motion we determine the acceleration;

v² = u² + 2as

0 = (9.3)² + (2x42)a

- 84a = 86.49

a = -86.49/84

|a| = 1.0296

F_k = \mu_k N = ma

where;

Fk is the frictional force

μk is the coefficient of kinetic friction

N is the normal reaction = mg

μkmg = ma

μkg = a

μk = a/g

where;

g is the gravitational constant = 9.8 m/s²

μk = a/g

μk = 1.0296/9.8

μk = 0.11

Therefore, the coefficient of kinetic friction between the puck and the ice is 0.11

3 0
3 years ago
A Ferris wheel has diameter of 10 m. It rotates at a uniform rate and makes one revolution in 8.0 seconds. A person weighing 670
Nikolay [14]

Answer:  459.14 N

Explanation:

from the question, we have

diameter = 10 m

radius (r)  = 5 m

weight (Fw) = 670 N

time (t) = 8 seconds

Circular motion has centripetal force and acceleration pointing perpendicular and inwards of the path, therefore we apply the equation below

∑ F = F c =  F w − Fn ..............equation 1

Fn = Fw − Fc = mg − (mv^2 / r) ...................equation 2

substituting the value of v as (2πr / T) we now have

Fn = mg − (m(2πr / T )^2) / r

Fn= mg − (4(π^2)mr / T^2)   ..........equation 3

Fw (mass of the person) = mg

therefore m = Fw / g

                m = 670 / 9.8 = 68.367 kg

now substituting  our values into equation 3

Fn = 670 - ( (4 x (π^2) x 68.367 x 5 ) / 8^2)

Fn = 670 - 210.86

Fn = 459.14 N

4 0
3 years ago
Why are bathroom tiles usually rough
Aleks04 [339]
-- Bathroom tiles are usually cool, so water condenses on them
when you take a hot bath or shower in the room. 

-- The natural result is that a smooth tile would become slippery,
exactly when you're walking around with wet feet and nothing on them ...
a dangerous situation.

-- In order to circumvent this safety hazard, the tiles in the bathroom
should be rough, especially on the floor.
8 0
3 years ago
You serve a volleyball with a mass of 2.5 kg. The ball leaves your hand with a speed of 23 m/s. What is the kinetic energy of th
Zarrin [17]

Answer:

661.25, I believe!

Explanation:

KE = (1/2)(2.5)(23)^2

KE=(1.25)(529)

KE= 661.25

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3 years ago
. Strong language often means
san4es73 [151]
I would say that strong language typically reveals strong feelings: strong language would reveal desperation, or very strong feelings: weak feelings would not demand it, and would be more likely accompanied by more controlled behavior.
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