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4 years ago

Heyy,Can you help me to do this physics problem:

Physics

1 answer:

Kobotan [32]4 years ago

5 0

Answer:

Average Speed = (Total distance)/(Total Time) = (1800 + 1800)/(30 + 45) = 3600/75 = 48 km/hr. Hence the correct option here is C) 48 km/hr. So to find the average speed never use the formula of the averages but try to find the total distance covered and the total time taken.

Explanation:

It is equals to distance divided time

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Why is it not advisable to sterilize clinical thermometer with boiling water

amm1812

It will break. A clinical the emoter is designed to measure relatively small changes in temperature. The substance inside a clinical thermoset will expand or evaporate at boiling temperatures and break.

6 0

3 years ago

A railroad car of mass 2.00 3 104 kg moving at 3.00 m/s collides and couples with two coupled railroad cars, each of the same ma

FrozenT [24]

Given:

Mass of the rail road car, m = 2 kg

velocity of the three cars coupled system, v' = 1.20 m/s

velocity of first car, $v_{a}$ = 3 m/s

Solution:

a) Momentum of a body of mass 'm' and velocity 'v' is given by:

p = mv

Now for the coupled system according to law of conservation of momentum, total momentum of a system before and after collision remain conserved:

$mv_{a} + 2mv_{b} = (m + 2m)v'$ (1)

where,

$v_{a}$ = velocity of the first car

$v_{b}$ = velocity of the 2 coupled cars after collision

Now, from eqn (1)

$v' = \frac{v_{a} + 2v_{b}}{3}$

$v' = \frac{3.00 + 2\times 1.20}}{3}$

v' = 1.80 m/s

Therefore, the velocity of the combined car system after collision is 1.80 m/s

7 0

3 years ago

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What question did use of a telescope by hubble answer A) Is earth the center of the universe B) Is the sun the center of the uni

cestrela7 [59]

Answer: C

Explanation:

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3 years ago

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A hockey puck on a frozen pond is given an initial speed of 20.0 m/s. If the puck always remains on the ice and slides 115 m bef

bekas [8.4K]

Answer:

μ_k = 0.1773

Explanation:

We are given;

Initial velocity;u = 20 m/s

Final velocity;v = 0 m/s (since it comes to rest)

Distance before coming to rest;s = 115 m

Let's find the acceleration using Newton's second law of motion;

v² = u² + 2as

Making a the subject, we have;

a = (v² - u²)/2s

Plugging relevant values;

a = (0² - 20²)/(2 × 115)

a = -400/230

a = -1.739 m/s²

From the question, the only force acting on the puck in the x direction is the force of friction. Since friction always opposes motion, we see that:

F_k = −ma - - - (1)

We also know that F_k is defined by;

F_k = μ_k•N

Where;

μ_k is coefficient of kinetic friction

N is normal force which is (mg)

Since gravity acts in the negative direction, the normal force will be positive.

Thus;

F_k = μ_k•mg - - - (2)

where g is acceleration due to gravity.

Thus,equating equation 1 and 2,we have;

−ma = μ_k•mg

m will cancel out to give;

-a = μ_k•g

μ_k = -a/g

g has a constant value of 9.81 m/s², so;

μ_k = - (-1.739/9.81)

μ_k = 0.1773

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4 years ago

What is the difference in electrical potential energy between two places in an electric field?

Phoenix [80]

Answer: Option (c) is the correct answer.

Explanation:

The difference in electrical potential energy between two places in an electric field is known as potential difference.

Mathematically, potential difference between two given points can be written as follows.

$\Delta V = V_{2} - V_{1}$

where, $\Delta V$ = potential difference

$V_{1}$ = potential at point 1

$V_{1}$ = potential at point 2

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3 years ago

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