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3 years ago

A car is traveling at 10 m/s. 10 seconds later the car is traveling 40 m/s. What is the car’s acceleration?

Physics

1 answer:

ratelena [41]3 years ago

3 0

Answer:

a = 3 m/s^2

Explanation:

Vi = 10 m/s

Vf = 40 m/s

t = 10 s

Plug those values into the following equation:

Vf = Vi + at

40 = 10 + 10a

---> a = 3 m/s^2

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3. The electric field of a sinusoidal electromagnetic wave has an amplitude of 5.0 V/m. How much radiation energy passes through

True [87]

Answer:

e) $179$ J

Explanation:

$E_{o}$ = Magnitude of electric field = 5 V/m

$A$ = Area of window = 1.5 m²

$c$ = speed of electromagnetic wave = 3 x 10⁸ m/s

$\Delta t$ = time interval = 1 h = 3600 sec

radiation energy is given as

$U = (0.5)\epsilon _{o}E_{o}^{2}cA\Delta t$

$U = (0.5)(8.85\times 10^{-12})(5)^{2}(3\times 10^{8})(1.5)(3600)$

$U = 179$ J

6 0

2 years ago

a trampoline launches a 50kg person 2m into the air. if the springs push with 1960N of force, how much displacement was there in

Lina20 [59]

Answer: 0.5 m

Explanation:

Given

Mass of the person is $m=50\ kg$

Trampoline launches the person into the air up to height of $h=2\ m$

Force experience by springs is $F=1960\ N$

Here, the work done on displacing the springs is equivalent to the Potential energy acquired by the person i.e.

$\Rightarrow F\cdot x=mgh\quad [\text{x=displacement of the trampoline}]\\\\\text{Insert the values}\\\\\Rightarrow x=\dfrac{50\times 9.8\times 2}{1960}\\\\\Rightarrow x=\dfrac{980}{1960}\\\\\Rightarrow x=0.5\ m$

6 0

2 years ago

Read 2 more answers

11) A sled is initially given a shove up a frictionless 35º incline. It reaches a maximum height of 2.5

Andrej [43]

Answer:

7 m/s

Explanation:

To solve this problem you must use the conservation of energy.

$K1 +U1=K2+U2$

That math speak for, initial kinetic energy plus initial potential energy equals final kinetic energy plus final potential energy.

The initial PE (potential energy) is 0 because it hasn't been raised in the air yet. The final KE (kinetic energy) is 0 because it isn't moving. This gives the following:

$KE1= \frac{1}{2}mv^{2}}$

$PE2=mgh$

K1=U2

$\frac{1}{2} mv^{2} =mgh$

Solve for v

$v=\sqrt{2gh}$

Input known values and you get 7 m/s.

5 0

2 years ago

Exoplanets (planets outside our solar system) are an active area of modern research. Suppose astronomers find such a planet that

Leno4ka [110]

Answer:

8.829 m/s²

Explanation:

M = Mass of Earth

m = Mass of Exoplanet

$g_e$ = Acceleration due to gravity on Earth = 9.81 m/s²

g = Acceleration due to gravity on Exoplanet

$m=M-0.1M\\\Rightarrow m=0.9M$

$g_e=G\frac{M}{r^2}$

$g=G\frac{0.9M}{r^2}$

Dividing the equations we get

$\frac{g}{g_e}=\frac{G\frac{0.9M}{r^2}}{G\frac{M}{r^2}}\\\Rightarrow \frac{g}{g_e}=0.9\\\Rightarrow g=0.9g_e\\\Rightarrow g=0.9\times 9.81\\\Rightarrow g=8.829\ m/s^2$

Acceleration due to gravity on the surface of the Exoplanet is 8.829 m/s²

3 0

3 years ago

A car moves with a speed 72km/h, the driver uses the brakes, the car stops after 8 seconds, calculate its speed after 10 seconds

vampirchik [111]

The acceleration of the car is solved by subtracting the initial speed from the final speed then dividing the result by the elapsed time.

initial speed = 72 km/hr = 20 m/s

final speed = 0 m/s

elapsed time = 5 seconds

acceleration = (0 m/s – 20 m/s) / 5 s

acceleration = - 20m/s / 5 s

acceleration = -4 m/s^2

8 0

2 years ago