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LenaWriter [7]
2 years ago
10

A car covers 120 km in 3 hours calculate its speed in m/s​

Physics
2 answers:
dexar [7]2 years ago
7 0

Solution :—

120 km = 120 x 1,000 = 120,000 m

3 hours 3 x 60 x 60 = 3600

3600 x 3 = 10,800 s

speed = \frac{120,000}{10,800}

=\frac{1200}{108}

= 11.1 m/s

8_murik_8 [283]2 years ago
6 0

Answer:

11.1 m/s

Explanation:

120 km = 120 x 1,000 = 120,000 m

3 hours = 3 x 60 x 60 = 3600 x 3 = 10,800 s

speed = 120,000 / 10,800

= 1200/108

= 11.1 m/s

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How fast would the car need to go to double its kinetic energy?
boyakko [2]

Answer:

v_{f} = \sqrt{2}\cdot v_{o}

Explanation:

Let consider a car travelling at a speed v_{o}. The ratio of final kinetic energy to initial kinetic energy:

\frac{\frac{1}{2}\cdot m \cdot v^{2}_{f} }{\frac{1}{2}\cdot m \cdot v^{2}_{o}} = 2

\frac{v_{f}}{v_{o}} = \sqrt{2}

The final speed is:

v_{f} = \sqrt{2}\cdot v_{o}

3 0
3 years ago
Read 2 more answers
Two charged objects separated by some distance attract each other. If the charges on both objects are doubled with no change in
beks73 [17]

Answer:

a. the force between them quadruples

Explanation:

The electrostatic force between two charges is given by

F=k\frac{q_1 q_2}{r^2}

where

k is the Coulomb's constant

q1 and q2 are the two charges

r is the separation between the two charges

In this problem, the charges on both objects are doubled, so

q_1' = 2q_1\\q_2' = 2q_2

While the distance does not change, so the new force will be

F'= k \frac{(2q_1)(2q_2)}{r^2}=4 (k\frac{q_1 q_2}{r^2})=4 F

so, the force will quadruple.

4 0
3 years ago
Two engineering students, John with a weight of 96 kg and Mary with a weight of 48 kg, are 30 m apart. Suppose each has a 0.04%
djyliett [7]

Answer:

6.8370869499\times 10^{20}\ N

Explanation:

N_A = Avogadro's number = 6.022\times 10^{23}

e = Charge of electron = 1.6\times 10^{-19}\ C

k = Coulomb constant = 8.99\times 10^{9}\ Nm^2/C^2

Z = Atomic number of water = 18

M = Molar mass of water = 0.018 kg/mol

m = Mass of person

The charge is given by

q=imbalance\times n\times e

Total number of protons and electrons in each sphere

n=\dfrac{mN_AZe}{M}

q=imbalance\times \dfrac{mN_AZe}{M}

q_1=0.0004\times \dfrac{96\times 6.022\times 10^{23}\times 18\times 1.6\times 10^{-19}}{0.018}\\\Rightarrow q_1=3699916.8\ C

q_2=0.0004\times \dfrac{48\times 6.022\times 10^{23}\times 18\times 1.6\times 10^{-19}}{0.018}\\\Rightarrow q_1=1849958.4\ C

Electrical force is given by

F=\dfrac{kq_1q_2}{r^2}\\\Rightarrow F=\dfrac{8.99\times 10^{9}\times 3699916.8\times 1849958.4}{30^2}\\\Rightarrow F=6.8370869499\times 10^{20}\ N

The electrostatic force of attraction between them is 6.8370869499\times 10^{20}\ N

4 0
3 years ago
DONT ANSWER WITH A LINK PLEASE I NEED AN ANSWER FROM SOMEONE!
rjkz [21]
At 4 m/s?

How do the two kinetic energies compare to one another? QUADRUPLES !

#3 What is the kinetic energy of a 2,000 kg bus that is moving at 30 m/s?

Potential energy
3 0
3 years ago
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When a body is moving with a uniform velocity, the acceleration is ___?
denis23 [38]
<span>According to the formula : 
</span><span>a=<span><span>ΔV / </span><span>ΔT
</span></span></span><span>When a body is moving with a uniform velocity, the acceleration is zero. That's it. You should remember, that velocity is not constant whereas speed is constant.</span>
4 0
3 years ago
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