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3 years ago

A body moving with a velocity of 20m/s begins to accelerate at 3 m/s 2 . How far does the body move in 3 seconds

1 answer:

5 0

Given v_in = 20 m/s and a = 3 m/s2, assuming that the body moves at constant acceleration, the motion is modeled by the equation:

s(t) = (v_in)t + (1/2)a(t^2)

where s(t) is the distance traveled

substituting the given,

s(t) = 20t + (3/2)(t^2)

at t = 3

s(t) = 20(3) + (3/2)(3)^2

= 73.5 m

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Need help with 1 A and 1 B

Bingel [31]

I hate this class .....

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3 years ago

(a) A light-rail commuter train accelerates at a rate of 1.35 m/s2 . How long does it take to reach its top speed of 80.0 km/h,

Mashcka [7]

Answer:

(a) Time t = 16.46 sec

(b) Time t =13.466 sec

Explanation:

(a) As the train starts from rest its initial velocity u = 0 m/sec

Acceleration $a=1.35m/sec^2$

Final speed v = 80 km/hr

$80km/hr=\frac{80\times 1000}{3600sec}=22.22m/sec$

From first equation of motion v =u+at

So $t=\frac{v-u}{a}=\frac{22.22-0}{1.35}=16.46 sec$

(b) Now initial speed u = 22.22 m/sec

As finally train comes to rest so final speed v=0 m/sec

Deceleration $a=1.65m/sec^2$

So $t=\frac{v-u}{a}=\frac{0-22.22}{-1.65}=13.466 sec$

Final velocity v = 0 m/sec

Time t = 8.30 sec

So acceleration is given by

$a=\frac{v-u}{t}=\frac{0-22.22}{8.3}=-2.6771m/sec^2$

As acceleration is negative so it is a deceleration

7 0

3 years ago

Using newtons second law of motion, how fast for 100 KG object accelerates 350 N of force is applied to

fenix001 [56]

Answer:

3.5m/s^2

Explanation:

From Newton's second Law of Motion

F = ma

Where F is the applied force, m is the mass of the object and a is the acceleration.

F = 350 N

Mass = 100kg

350N = 100×a

a = 350/100

a = 3.5m/s^2

The acceleration of the object will be 3.5m/s^2

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3 years ago

Select the correct answer. Which of the following causes air pollution inside the house? A. Smoking cigarettes B. Growing housep

Troyanec [42]

Answer: Smoking cigarettes

Explanation: The other options don't cause pollution to form in the air besides smoking, from the particles it creates causing harm and damage to your lungs and fill the air with smoke particles.

3 0

2 years ago

Read 2 more answers

You are on a 4 m high ladder and throw a ball upwards at 12 m/s. It lands on the ground below the ladder.

Gelneren [198K]

a) 2.75 s

The vertical position of the ball at time t is given by the equation

$y= h+ut-\frac{1}{2}gt^2$

where

h = 4 m is the initial height of the ball

u = 12 m/s is the initial velocity of the ball (upward)

g = 9.8 m/s^2 is the acceleration of gravity (downward)

We can find the time t at which the ball reaches the ground by substituting y=0 into the equation:

$0 = 4 + 12t - 4.9 t^2$

This is a second-order equation. By solving it for t, we find:

t = -0.30 s

t = 2.75 s

The first solution is negative, so we discard it; the second solution, t = 2.75 s, is the one we are looking for.

b) -15.0 m/s (downward)

The final velocity of the ball can be calculated by using the equation:

$v=u-gt$

where

u = 12 m/s is the initial (upward) velocity

g = 9.8 m/s^2 is the acceleration of gravity (downward)

t is the time

By subsisuting t = 2.75 s, we find the velocity of the ball as it reaches the ground:

$v=12 -(9.8)(2.75)=-15.0 m/s$

And the negative sign means the direction is downward.

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2 years ago