All categories

3 years ago

How fast must a train accelerates from rest to cover 518 m in the first 7.48 s?

Physics

1 answer:

Rus_ich [418]3 years ago

8 0

Heya!

For this problem, use the formula:

s = Vo * t + (at^2) / 2

Since the initial velocity is zero, the formula simplifies like this:

s = (at^2) / 2

Clear a:

2s = at^2

(2s) / t^2 = a

a = (2s) / t^2

Data:

s = Distance = 518 m

t = Time = 7,48 s

a = Aceleration = ¿?

Replace according formula:

a = (2*518 m) / (7,48 s)^2

Resolving:

a = 1036 m / 55,95 s^2

a = 23,34 m/s^2

The aceleration must be <u>23,34 meters per second squared</u>

You might be interested in

A rope is tied to a box and used to pull the box 2.3 m along a horizontal floor. The rope makes an angle of 30∘ with the horizon

Savatey [412]

Answer:

Answered

Explanation:

A) The work done by gravity is zero because displacement and the gravitational force are perpendicular to each other.

W= FS cosθ

θ= 90 ⇒cos90 = 0 ⇒W= 0

B) work done by tension

W= Tcosθ×S= 5cos30×2.30= 10J

C) Work done by friction force

W= f×s=1×2.30= 2.30 J

D) Work done by normal force is Zero because the displacement and the normal force are perpendicular to each other.

E) The net work done= Work done by tension in the rope - frictional work

=10-2.30= 7.7 J

6 0

3 years ago

Please help :/ The same motor is used in rockets with different masses. The rockets have different accelerations. According to N

Ymorist [56]

Answer:

1. As rocket mass increases, acceleration decreases.

2. The inverse of the mass of the boat.

Explanation:

1. Newton's second law of motion states;

F = ma

where F is the force applied, m is the mass and a is the acceleration.

Therefore, increasing the mass of a rocket increases its weight which would reduce its acceleration provided that the force is constant. Thus, as rocket mass increases, acceleration decreases.

2. The slope of the graph can be expressed as;

From Newton's second law,

F = ma

Slope = (Δa) ÷ (ΔF)

Slope = $\frac{a}{F}$

⇒ $\frac{1}{m}$ = $\frac{a}{F}$

Therefore, the slope of the graph is the reciprocal of the mass of the boat.

7 0

3 years ago

Sliding friction is affected by the weight of the object.<br><br> True or false

Dmitry [639]

Yes that is correct or in other form, True

7 0

3 years ago

Read 2 more answers

How much tension must a rope withstand if it is used to accelerate a 6526 kg car vertically upwards at 8.9 m/s^2?

ExtremeBDS [4]

Answer:

The value is $T = 122036.2 \ N$

Explanation:

From the question we are told that

The mass of the car is $m = 6526 \ kg$

The acceleration is $a= 8.9 \ m/s^2$

Generally the net force applied on the rope is mathematically represented as

$F_{net} = T - W$

Here W is the weight of the car which is evaluated as

$W = m * g$

=> $W = 6526 * 9.8$

=> $W = 63954.8 \ N$

Generally the net force can also be mathematically represented as

$F = m * a$

$m * a = T - 63954.8$

=> $6526 * 8.9 = T - 63954.8$

=> $T = 122036.2 \ N$

7 0

3 years ago

While at a construction site, you see a crane lift a 1000kg steel beam up to a height of 10m in a time period of 5.0 seconds. A

storchak [24]

Answer:

Car has more power output than crane

Explanation:

We have given that mass of the crane m = 1000 kg

Height through which crane lift the steel beam h = 10 m

Acceleration due to gravity $g=9.8m/sec^2$

So work done by crane $W=mgh=1000\times 9.8\times 10=98000j$

Time period is given as t = 5 sec

We know that power $P=\frac{W}{t}=\frac{98000}{5}=19600watt$

Now mass of the car = 1000 kg

Initial velocity u = 0 m /sec

Final velocity v = 10 m/sec

We know that work done is equal to the change in kinetic energy

So work done $=\frac{1}{2}mv^2-\frac{1}{2}mu^2$

$=\frac{1}{2}\times 1000\times 10^2-\frac{1}{2}\times 1000\times 0^2=50000j$

Time ids given as t = 2 sec

So power $P=\frac{W}{t}=\frac{50000}{2}=25000watt$

So car has more power output than crane

8 0

3 years ago