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2 years ago

Using this formula Vj = V; + at, If a vehicle starts from rest

Physics

1 answer:

Furkat [3]2 years ago

5 0

Answer:

<em>The final speed of the vehicle is 36 m/s</em>

Explanation:

<u>Uniform Acceleration</u>

When an object changes its velocity at the same rate, the acceleration is constant.

The relation between the initial and final speeds is:

$v_f=v_o+a.t$

Where:

vf = Final speed

vo = Initial speed

a = Constant acceleration

t = Elapsed time

The vehicle starts from rest (vo=0) and accelerates at a=4.5 m/s2 for t=8 seconds. The final speed is:

$v_f=0+4.5*8$

$v_f=36\ m/s$

The final speed of the vehicle is 36 m/s

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A dockworker applies a constant horizontal force of 80.0 N to a block of ice on a smooth horizontal floor. The frictional force

Tamiku [17]

Answer:

(a) 91 kg (2 s.f.) (b) 22 m

Explanation:

Since it is stated that a constant horizontal force is applied to the block of ice, we know that the block of ice travels with a constant acceleration and but not with a constant velocity.

(a)

$s \ = \ ut \ + \ \displaystyle\frac{1}{2} at^{2} \\ \\ a \ = \ \displaystyle\frac{2(s \ - \ ut)}{t^{2}} \\ \\ a \ = \ \displaystyle\frac{2(11 \ - \ 0)}{5^{2}} \\ \\ a \ = \ \displaystyle\frac{22}{25} \\ \\ a \ = \ 0.88 \ \mathrm{m \ s^{-2}}$

Subsequently,

$F \ = \ ma \\ \\ m \ = \ \displaystyle\frac{F}{a} \\ \\ m \ = \ \displaystyle\frac{80 \ \mathrm{kg \ m \ s^{-2}}}{0.88 \ \mathrm{m \ s^{-2}}} \\ \\ m \ = \ 91 \mathrm{kg} \ \ \ \ \ \ (2 \ \mathrm{s.f.})$

*Note that the equations used above assume constant acceleration is being applied to the system. However, in the case of non-uniform motion, these equations will no longer be valid and in turn, calculus will be used to analyze such motions.

(b) To find the final velocity of the ice block at the end of the first 5 seconds,

$v \ = \ u \ + \ at \\ \\ v \ = \ 0 \ + \ (0.88 \mathrm{m \ s^{-2}})(5 \ \mathrm{s}) \\ \\ v \ = \ 4.4 \ \mathrm{m \ s^{-1}}$

According to Newton's First Law which states objects will remain at rest

or in uniform motion (moving at constant velocity) unless acted upon by

an external force. Hence, the block of ice by the end of the first 5

seconds, experiences no acceleration (a = 0) but travels with a constant

velocity of 4.4 $m \ s^{-1}$ .

$s \ = \ ut \ + \ \displaystyle\frac{1}{2}at^{2} \\ \\ s \ = \ (4.4 \ \mathrm{m \ s^{-2}})(5 \ \mathrm{s}) \ + \ \displaystyle\frac{1}{2}(0)(5^{2}) \\ \\ s \ = \ 22 \ \mathrm{m}$

Therefore, the ice block traveled 22 m in the next 5 seconds after the

worker stops pushing it.

4 0

2 years ago

Perform the following mathematical operation and report answer to the correct number of significant figures 143.6 divided by 21.

Svetllana [295]

The answer to the correct number of significant figures is 6.774.

<h3>What is quotient?</h3>

When a number(big) divided smaller number, the answer obtained greater than zero is called a quotient.

Divide 143.6 ÷ 21.2

143.6/21.2 = 1436/212

=6.77358

The quotient is rounded to three significant figures after decimal

143.6 ÷ 21.2 = 6.774

Thus, the answer to the correct number of significant figures is 6.774

Learn more about quotient

brainly.com/question/27796160

#SPJ1

7 0

1 year ago

A block of weight mg sits on an inclined plane as shown in (Figure 1) . A force of magnitude F1 is applied to pull the block up

svlad2 [7]

Answer:

W = (F1 - mg sin θ) L, W = -μ mg cos θ L

Explanation:

Let's use Newton's second law to find the friction force. In these problems the x axis is taken parallel to the plane and the y axis perpendicular to the plane

Y Axis

N - $W_{y}$ =

N = W_{y}

X axis

F1 - fr - Wₓ = 0

fr = F1 - Wₓ

Let's use trigonometry to find the components of the weight

sin θ = Wₓ / W

cos θ = W_{y} / W

Wₓ = W sin θ

W_{y} = W cos θ

We substitute

fr = F1 - W sin θ

Work is defined by

W = F .dx

W = F dx cos θ

The friction force is parallel to the plane in the negative direction and the displacement is positive along the plane, so the Angle is 180º and the cos θ= -1

W = -fr x

W = (F1 - mg sin θ) L

Another way to calculate is

fr = μ N

fr = μ W cos θ

the work is

W = -μ mg cos θ L

4 0

3 years ago

After a package is dropped from the plane, how long will it take for it to reach sea level from the time it is dropped? assume t

Ivenika [448]

Time taken by the package to reach the sea level= 13.7 s

height=h=925 m

initial velocity along vertical= vi=0

acceleration due to gravity=g=9.8 m/s^2

using the kinematic equation h= Vi*t + 1/2 gt^2

925=0(t)+1/2 (9.8)t^2

4.9 t^2=925

t= 13.7 s

6 0

3 years ago

The energy transferred from the water in the kettle to the surroundings in 2 hours is

nignag [31]

The Last one ☝️ I think

6 0

2 years ago