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3 years ago

What Initial Velocity would you have to give the Marble to make it hit the ground in 5 s

Physics

2 answers:

Paraphin [41]3 years ago

5 0

Answer:

-49 m/s

Explanation:

You would use the formula vf = vi + at, where vf stands for final velocity, vi stands for initial velocity, a stands for acceleration, and t stands for time. Assuming you're dropping the marble on Earth, the acceleration would be -9.8m/s², and the final velocity would be 0 m/s, as it stops after hitting the ground. (0 = vi + (9.8)(5))

Yakvenalex [24]3 years ago

4 0

Answer:

Traveling 381m in 5 seconds means the average velocity is: 381m/5s = 76.2 m/s.

Explanation:

Letting x be the initial velocity and v the final velocity, we have:

12(x+v)=76.2m/s

and (since v=x+50),

12(2x+50)=76.2m/s

x+25=76.2m/s

x=51.2m/s

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A car is moving with a constant velocity of 25 m/s. Which of the following is true?

S_A_V [24]

b) the net force on the car is zero.

Explanation:

Let's analyze each option one by one:

a) the force from the engine is greater than all the forces of friction. --> FALSE. In fact, the car is moving at constant velocity: this means that its acceleration is zero,

a = 0

and so Newton's second law becomes

$\sum F = ma = 0$

where $\sum F$ is the net force on the car and m is its mass. This means that the net force on the car is zero: so, the force from the engine cannot be greater than all the forces of friction, otherwise the net force cannot be zero.

b) the net force on the car is zero. --> TRUE, for what we said at point A)

c) the inertia is changing. --> FALSE. The inertia of an object just depend on the mass and the velocity of the object: as neither the mass nor the velocity are changing in this problem, then the inertia of the car is not changing.

d) the forces of friction are proportional to the acceleration of the car. --> FALSE. Generally, the force of friction acting on an object moving on a flat surface is

$F_f = \mu mg$

where $\mu$ is the coefficient of friction, m is the mass, and g the acceleration of gravity. Therefore, the force of friction does not depend on the acceleration of the car.

e) All of the above. --> FALSE

Learn more about net force and Newton's second law:

brainly.com/question/3820012

#LearnwithBrainly

6 0

3 years ago

An observer standing near a window 5 m high observe that an object falling downwards is passing across the window in 0.5 s. Find

Valentin [98]

Answer:

Explanation:

An object in free fall, NOT experiencing parabolic motion, has an equation of

$h(t)=\frac{1}{2} gt^2+h_0$ which says:

The height of an object with respect to time in seconds is equal to the pull of gravity times time-squared plus the height from which it was dropped. Normally we use -9.8 for gravity but you said to use 10, so be it.

For us, h(t) is 5 because we are looking for the height of the window when the object is 5 m off the ground at .5 seconds;

g = 10 m/s/s, and

t = .5sec

$5=\frac{1}{2}(-10)(.5)^2$ +h and

5 = -5(.5)² + h and

5 = -5(.25) + h and

5 = -1.25 + h so

h = 6.25

That's how high the window is above the ground.

8 0

2 years ago

A basketball player can jump 1.6 m off the hardwood floor. With what upward velocity did he leave the floor?

irinina [24]

First do 1.6 m (how far he jumps) 9.8 m/s (what gravity is measured at) then times 2

= 31.36

Sq root = 5.6

3 0

3 years ago

Read 2 more answers

a car travelling at 50m/h on a horizontal highway (a) if the coefficient of static friction between road and tyres on a rainy da

aleksandrvk [35]

Hope this helps!

-Lilly

3 0

3 years ago

The total electric flux from a cubical box 26.0 cm on a side is 1840 N m2/C. What charge is enclosed by the box?

vitfil [10]

The expression of the electric flux is

$\Phi = \frac{Q}{\epsilon_0}$

Here,

Q = Total charge enclosed in the closed surface

$\epsilon_0$ = Permittivity due to free space

Rearranging to find the charge,

$Q = \epsilon_0 \Phi$

Replacing with our values we have finally

$Q = (8.85*10^{-12}F\cdot m^{-1})(1.84*10^3 N\cdot m^2/C)$

$Q = 1.6284*10^{-8} C$ $(\frac{10^9nC}{1C})$

$Q = 0.1684nC$

The charge enclosed by the box is 0.1684nC

The sign of the charge can be decided by using the direction of the flux. The charge enclosed by the cube can be calculated by using the electric flux and the permitivity of free space.

7 0

3 years ago