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sergey [27]
3 years ago
8

A train travels with a constant speed of 20.0m/s for 7.00s. Determine all

Physics
1 answer:
Bad White [126]3 years ago
8 0

Answer:

acceleration is zero m/s²

Explanation:

It is given that the train travels at constant speed (i.e speed does not change)

If speed does not change, then the train is neither accelerating or decelerating (i.e acceleration is zero)

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HEY CAN ANYONE PLS ANSWER DIS!!!!!!!!!!!!
Salsk061 [2.6K]

Answer:

a is falsa

Explanation:

8 0
3 years ago
In 1999, Robbie Knievel was the first to jump the Grand Canyon on a motorcycle. At a narrow part of the canyon (65 m wide) and t
vfiekz [6]

Answer:

His launching angle was 14.72°

Explanation:

Please, see the figure for a graphic representation of the problem.

In a parabolic movement, the velocity and displacement vectors are two-component vectors because the object moves along the horizontal and vertical axis.

The horizontal component of the velocity is constant, while the vertical component has a negative acceleration due to gravity. Then, the velocity can be written as follows:

v = (vx, vy)

where vx is the component of v in the horizontal and vy is the component of v in the vertical.

In terms of the launch angle, each component of the initial velocity can be written using the trigonometric rules of a right triangle (see attached figure):

sin angle = opposite / hypotenuse

cos angle = adjacent / hypotenuse

In our case, the side opposite the angle is the module of v0y and the side adjacent to the angle is the module of vx. The hypotenuse is the module of the initial velocity (v0). Then:

sin angle = v0y / v0  then: v0y = v0 * sin angle

In the same way for vx:

vx = v0 * cos angle

Using the equation for velocity in the x-axis we can find the equation for the horizontal position:

dx / dt = v0 * cos angle

dx = (v0 * cos angle) dt (integrating from initial position, x0, to position at time t and from t = 0 and t = t)

x - x0 = v0 t cos angle

x = x0 + v0 t cos angle

For the displacement in the y-axis, the velocity is not constant because the acceleration of the gravity:

dvy / dt = g ( separating variables and integrating from v0y and vy and from t = 0 and t)

vy -v0y = g t

vy = v0y + g t

vy = v0 * sin angle + g t

The position will be:

dy/dt = v0 * sin angle + g t

dy = v0 sin angle dt + g t dt (integrating from y = y0 and y and from t = 0 and t)

y = y0 + v0 t sin angle + 1/2 g t²

The displacement vector at a time "t" will be:

r = (x0 + v0 t cos angle, y0 + v0 t sin angle + 1/2 g t²)

If the launching and landing positions are at the same height, then the displacement vector, when the object lands, will be (see figure)

r = (x0 + v0 t cos angle, 0)

The module of this vector will be the the total displacement (65 m)

module of r = \sqrt{(x0 + v0* t* cos angle)^{2} }  

65 m = x0 + v0 t cos angle ( x0 = 0)

65 m / v0 cos angle = t

Then, using the equation for the position in the y-axis:

y = y0 + v0 t sin angle + 1/2 g t²

0 =  y0 + v0 t sin angle + 1/2 g t²

replacing t =  65 m / v0 cos angle and y0 = 0

0 = 65m (v0 sin angle / v0 cos angle) + 1/2 g (65m / v0 cos angle)²  

cancelating v0:

0 = 65m (sin angle / cos angle) + 1/2 g * (65m)² / (v0² cos² angle)

-65m (sin angle / cos angle) = 1/2 g * (65m)² / (v0² cos² angle)  

using g = -9.8 m/s²

-(sin angle / cos angle) * (cos² angle) = -318.5 m²/ s² / v0²

sin angle * cos angle = 318.5 m²/ s² / (36 m/s)²

(using trigonometric identity: sin x cos x = sin (2x) / 2

sin (2* angle) /2 = 0.25

sin (2* angle) = 0.49

2 * angle = 29.44

<u>angle = 14.72°</u>

3 0
3 years ago
What disadvantage of convex mirror​
Eddi Din [679]

Answer:

The disadvantage is that convex mirror is that they make it appear like those objects are at a more noteworthy distance than they actually are. It always gives a virtual, erect and a diminished image.

Explanation:

5 0
3 years ago
initially, a bowl holds 15 m^3 of water. an object is dropped into the bowl and the new volume of the water is 25 m^3. what is t
marusya05 [52]

Explanation:

The new volume of water = 25 ml

The old volume of water = 15 ml

The difference = 25 - 15 but what are the units?

Since the question asks for force, the units must start out as 10 mL

In water 1 mL has a mass of 1 gram, so the answer is 10 grams.

Grams are units of mass, not weight. You should convert this into newtons.

10 grams = 1/1000 = 0.01 kg

1 kg has a weight of 9.81 Newtons

0.01 kg has a weight 0.081 Newtons

If you have never seen a Newton before, then the answer is 10 grams

3 0
3 years ago
A person weighing 645 N climbs up a ladder to a height of 4.55 m what is the increase in gravitational energy
Lemur [1.5K]

Answer: 2934.75 Joules

Explanation:

Potential energy can be defined as energy possessed by an object or body due to its position.

Mathematically, potential energy is given by the formula;

<em>P.E = mgh</em>

Where P.E represents potential energy measured in Joules.

m represents the mass of an object.

g represents acceleration due to gravity measured in meters per second square.

h represents the height measured in meters.

Given the following data;

Weight =645

Height = 4.55

<em>P.E = mgh</em>

But we know that weight = mg = 645N

Substituting into the equation, we have;

<em>P.E = 645 • 4.55</em>

<em>P.E = 2934.75J</em>

Potential energy, P.E = 2934.75 Joules.

3 0
3 years ago
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