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3 years ago

A parked car begins to roll down a hill, what can you conclude from that observation?

Physics

1 answer:

Fynjy0 [20]3 years ago

3 0

Answer:

its The rolling friction is greater than the force of the car’s weight against the hill.

and A force was required to start the car rolling.

Explanation:

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What is the scientific method

Alex_Xolod [135]

The scientific method is an empirical tool that can be used to study phenomenon by asking questions, conducting experiments, and making observations to prove or disprove hypotheses. The scientific method has been used as a baseline tool in hard and social sciences to conduct experiments and to make conclusions about phenomenon in our natural world.

7 0

3 years ago

Read 2 more answers

A block of plastic in the shape of a rectangular solid that has height 8.00 cm and area A for its top and bottom surfaces is flo

kifflom [539]

Answer:

0.35 kg

Explanation:

8 cm = 0.08 m

For the block to stay balance, the buoyancy force must be the same as gravity that pulls it down.

Let mass of the block be M, then the gravity would be Mg

Let water density be $\rho_w = 1000 kg/m^3$ , the buoyancy force would be the weight of water that is displaced by the submerged block.

For example, when there is no coin, block is $h_0 = 0.0312m$ submerged. The weight of water displaced must be

$W_0 = Ah_0\rho_wg = 0.0312A1000g = 31.2Ag$

Which is also the weight of block, of Mg

Therefore M = 31.2A. (1)

As coins are stacked on top of block, h increase, so as weight of water displaced and total weight of block and coins. Now let m be the total weight of coins. The gravity of block and weight must be (M+m)g. And the weight of water displaced is:

$W = Ah\rho g = (M + m)g$

$h = \frac{M}{A\rho} + \frac{m}{A\rho}$

Since the linear plot of h vs m has a slope of 0.089 m/kg, we can interpret it as

$\frac{1}{A\rho} = 0.089$

$A = \frac{1}{0.089\rho} = \frac{1}{89} = 0.011 m^2$

So from the eq. (1) we can solve for M = 31.2A = 0.35 kg

8 0

3 years ago

Water pressurized to 3.5 x 105 Pa is flowing at 5.0 m/s in a horizontal pipe which contracts to 1/3 its former area. What are th

masha68 [24]

Answer:

the pressure after contraction is 2×10^5 Pa

the speed after contraction is 15m/s

Explanation:

We were given Pressure P to be 3.5 x 10^5 that is Flowing with speed of 5.0 m/s,

For us to calculate pressure we need to calculate the area first as;

Let initial Area = A₁

And Final area A₂

We were told that in a horizontal pipe it contracts to 1/3 its former area. Which means

A₂= A₁/3.................

V₁ is the speed

the pressure and speed of the water after the contraction can be calculated using equation of continuity below

A₂V₂ = A₁V₁

But

If we substitute given value in the expresion we have

V₂ = (3A *5)/A

V₂ = 15m/s

Therefore, the speed after contraction is 15m/s

Now we can calculate the pressure using

Bernoulli's equation

p₁ + ½ρv₁² + ρgh₁ = p₂ + ½ρv₂² + ρgh₂

But we know that the pipe is horizontal, then "h" terms cancel out then

p₁ + ½ρv₁² = p₂ + ½ρv₂²

Making P₂ subject of formula we have

p₂ = 0.5ρ( V ₁² - v₂² ) + P₁

P₂=. 0.5 × 1000 (5² -15² ) + 3*10^5

=2×10^5 Pa

Therefore, the pressure after contraction is 2×10^5 Pa

7 0

3 years ago

Li is riding her bicycle at 8.0 m/s. She slows down to 4.0 m/s. Her change in velocity is m/s. If Li takes 2 seconds to make thi

forsale [732]

You will have to use this formula:
$v = vo + a \times t$

Final Velocity (V) = 4m/s
Initial Velocity (Vo) = 8m/s
Acceleration (a) = ? m/s^2
Time (t) = 2 secs

Then:

-> 4 = 8 + a x 2
-> 4 - 8 = 2a
-> -4 = 2a
-> a = -4/2
-> a = -2 m/s^2

Ps: It's value is negative because the she was in retrograde motion.

Answer: Her acceleration is -2 m/s^2.

4 0

4 years ago

Read 2 more answers

How do longitudinal waves transport energy?

marissa [1.9K]

A longitudinal wave transports energy through the medium without permanently transporting matter.

Hope this helps :D

6 0

3 years ago