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scoundrel [369]
3 years ago
14

A car is moving from rest and the velocity increases to 30 m/s in 4 seconds. Calculate its acceleration.

Physics
1 answer:
vaieri [72.5K]3 years ago
8 0

Answer:

7.5 m/s²

Explanation:

Given:

v₀ = 0 m/s

v = 30 m/s

t = 4 s

Find: a

v = at + v₀

(30 m/s) = a (4 s) + (0 m/s)

a = 7.5 m/s²

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How do I count atoms in science
VashaNatasha [74]

Answer:

The "2" tells us that there are 2 hydrogen atoms in this compound.

Explanation:

6 0
3 years ago
A 90 kg man stands in a very strong wind moving at 17 m/s at torso height. As you know, he will need to lean in to the wind, and
victus00 [196]

Answer:

a)  t=195.948N.m

b)  \phi=13.6 \textdegree

Explanation:

From the question we are told that:

Density \rho=1.225kg/m^2

Velocity of wind v=14m/s

Dimension of rectangle:50 cm wide and 90 cm

Drag coefficient \mu=2.05

a)

Generally the equation for Force is mathematically given by

F=\frac{1}{2}\muA\rhov^2

F=\frac{1}{2}2.05(50*90*\frac{1}{10000})*1.225*17^2

F=163.29

Therefore Torque

t=F*r*sin\theta

t=163.29*1.2*sin90

t=195.948N.m

b)

Generally the equation for torque due to weight is mathematically given by

t=d*Mg*sin90

Where

d=sin \phi

Therefore

t=sin \phi*Mg*sin90

195.948=833sin \phi

\phi=sin^{-1}\frac{195.948}{833}

\phi=13.6 \textdegree

5 0
3 years ago
At what distance from Earth does the force of gravity exerted by Earth on the coasting spacecraft cancel the force of gravity ex
telo118 [61]

Answer:

346 * 10⁶ m

Explanation:

The force of gravity of the earth that will cancel the the force of gravity exerted by the moon will be equal to each other

Let F_{e} be the force of gravity exerted by the earth

and let F_{m} be the force of gravity exerted by the moon

According to Newton's law of universal gravitation, the force of attraction between two different masses, m₁ and m₂ separated by a distance, d,  is given by:

F = \frac{Gm_{1} m_{2} }{d^{2} }

Mass of the earth, m_{e} = 5.97 * 10^{24} kg

Mass of the moon, m_{m} = 7.348 * 10^{22} kg

Mass of the satellite, m_{s} = ?

F_{e}  = \frac{G*5.97 * 10^{24} M }{d^{2} }...............................(1)

The earth and the moon are separated by a distance, 3.844 * 10⁸ m

F_{m}  = \frac{G*7.348 * 10^{22} M }{(3.844 * 10^{8} - d) ^{2} }............................(2)

Equating equations (1) and (2)

\frac{5.97 * 10^{24} }{d^{2} } = \frac{7.348 * 10^{24} }{(3.844* 10^{8} -d)^{2} }

(5.97 * 10^{24})(14.78 * 10^{16}  -7.688*10^{8}d + d^{2}) = 7.348 * 10^{24} d^{2} \\88.24*10^{40} - 45.9 * 10^{32}d +  5.97 * 10^{24}d^{2} =  7.348 * 10^{24} d^{2}\\ 1.378 * 10^{24}d^{2} + 45.9 * 10^{32}d + 88.24*10^{40} = 0\\

Factorising out 10^{24}

1.378d^{2} + 45.9 * 10^{8}d + 88.24*10^{16} = 0

Solving for d in the quadratic equation  above:

d = 346 * 10⁶ m

4 0
3 years ago
A baseball is thrown through the air. It's initial velocity, described as a vector, is → v ( t = 0 ) = 17.1 ˆ i + 14.7 ˆ j m / s
ludmilkaskok [199]

Answer:

 a = - 9.8 j ^   m/s²

Explanation:

This is a projectile launch problem, they give us the initial velocity in the two components

         v₀ₓ = 17.1 m / s

         v_{oy} = 14.7 m / s

They indicate that the only acceleration that exists is the acceleration of gravity, which acts in the direction towards the center of the Earth, in general in a coordinate system it coincides with the direction of the y axis.

           a = - g j ^

           a = - 9.8 j ^  m /s²

6 0
3 years ago
Please help :( A ray of laser light strikes a glass surface at an angle θa = 22.5° to the normal. What is the angle θb of the re
pshichka [43]

Answer:

Explanation:

We shall apply law of refraction which is as follows

sin i / sinr = μ  , where i is angle of incidence , r is angle of refraction and μ is refractive index

here i = θa = 22.5°

r = θb

μ  = 1.77

sin22.5 / sinθb = 1.77

.3826 / sinθb = 1.77

sinθb = .216

θb  = 12.5 °.

4 0
3 years ago
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