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A train has a constant speed of 10 m/s around a track with a diameter of 45 m what is the centripal acceleration?

Bumek [7]

Answer:

$a_{c}= 4.44\frac{m}{s}$

Explanation:

When an object goes on a circular movement, it has a centripetal acceleration that always points toward the center of the circle, it is the responsible of the change of direction in the movement of the object. and that centripetal acceleration is related with the speed in the next way:

$a_{c}=\frac{v^{2}}{r}$ , with v the speed, r the radius of the track that is half of the diameter (22.5 m)

$a_{c}=\frac{10^{2}}{22.5}$

$a_{c}= 4.44\frac{m}{s}$

5 0

3 years ago

For each of the following cases, indicate whether the net work done is positive, negative, or zero. (a) gravity acting on a fall

irina [24]

Answer:

Explanation:

We to indicate whether work is positive or negative or zero

Note, Work can be define as the produce of force and distance in the direction of the force, work is the dot product of force and displacement

W = F•d

(a) gravity acting on a falling ball

Work done acting on a falling ball is positive, since gravity does work on the ball. And g is positive downward.

Then, Work done by a free falling body is

W = mgh

(b) girl accelerating a wagon from rest

The workdone by a girl accelerating a wagon is positive

Since the wagon is a accelerating, then the velocity is increasing, then, the acceleration is positive

Work done by an accelerating car can be calculated be

W = F×d

Where the force is mass of the car times the positive acceleration

W = m•a•d

(c) a skydiver falling at terminal velocity through the air

The work done is zero since the terminal velocity is constant, so their is no change in velocity, the drag force is equal to the weight of the body and their is no external force acting on the body and the vertical acceleration goes to zero and since no acceleration, the work done is zero

W = m×a×h

W = 0J

But in this case, what is still don't by gravity. Since gravity is not zero.

(d) friction acting on a car so that it rolls to a stop.

The work done by friction is negative. This is due to the fact that the velocity of the car decreases with time and this implies that the car is decelerating, so the acceleration is negative, then,

W = m ×a × d

Since a =-ve

Then, W = —m•a•d

The work done by friction is negative

5 0

3 years ago

Which of the following is an example of an opposing force?

katovenus [111]

Answer:

d

Explanation:

i dont really know

6 0

2 years ago

Which is equal to a temperature of 50°F? a 18°C b 46°C c 10°C d 32°C

Orlov [11]

Answer: C: 10 degrees Celsius

Explanation: 50 degrees Fahrenheit equals 10 degrees Celsius.

4 0

2 years ago

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A daredevil jumps a canyon 10.9 m wide. To do so, he drives a car up a 24° incline. (The daredevil lands on the other side of th

Agata [3.3K]

Answer:

Minimum speed required = 12 m/s

Explanation:

Let the speed be y, and upward direction be positive

Consider the vertical motion of car:-

Initial velocity, u = ysin24

Acceleration, a = -9.81 m/s²

We need to find time when displacement is zero, ( s = 0m )

Substituting in s = ut + 0.5at²

0 = ysin24 x t + 0.5 x -9.81 x t²

4.905t² - ysin24 x t = 0

t (4.905t - ysin24 ) = 0

t = 0 or $t=\frac{ysin24}{4.905}=0.083y$

Here time = 0 is not considered,

So t = 0.083 y

Consider the vertical motion of car:-

Initial velocity, u = ycos24

Acceleration, a = 0 m/s²

Time, t = 0.083y

We need to find speed when displacement is 10.9 m, ( s = 10.9 m )

Substituting in s = ut + 0.5at²

10.9 = ycos24 x 0.083y + 0.5 x 0 x (0.083y)²

0.076y² = 10.9

y = 11.99 = 12 m/s

Minimum speed required = 12 m/s

3 0

3 years ago