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guapka [62]
3 years ago
9

A motorist wishes to travel 40 kilometers at an average speed of 40 km/h. During the first 20 kilometers, an average speed of 40

km/h is maintained. During the next 10 kilometers. however, the motorist averages only 20 km/h. To drive the remaining 10 kilometers and average 40 km/h, the motorist must drive
a) 60 km/h. b) 80 km/h. c) 90 km/h. d) faster than the speed of light​
Physics
1 answer:
allochka39001 [22]3 years ago
4 0

poste en français s’il vous plaît

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A ball with a mass of 3.1 kg is moving in a uniform circular motion upon a horizontal surface. The ball is attached at the cente
inessss [21]

Answer:

3.46 seconds

Explanation:

Since the ball is moving in circular motion thus centripetal force will be acting there along the rope.

The equation for the centripetal force is as follows -

F=\frac{mv^2}{r}

Where, m is the mass of the ball, v is the speed and r is the radius of the circular path which will be equal to the length of the rope.

This centripetal force will be equal to the tension in the string and thus we can write,

20.4 = \frac{3.1\times v^2}{2}

and, v^2 = 13.16

Thus, v = 3.63 m/s.

Now, the total length of circular path = circumference of the circle

Thus, total path length = 2πr = 2 × 3.14 × 2 = 12.56 m

Time taken to complete one revolution = \frac{\text {Path length} }{\text {Speed}} = \frac{12.56}{3.63} = 3.46 seconds.

Thus, the mass will complete one revolution in 3.46 seconds.

4 0
3 years ago
Jet fighter planes are launched from aircraft carriers with the aid of their own engines and a catapult. If in the process of be
ANTONII [103]

Answer:

W=315 x 10⁵ J

Explanation:

Given that

F= 2.5 x 10⁵ N

d= 90 m

K.E.=5.4 x 10⁷ J

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

Lets take work done by catapult is W

W + F.d= K.E.

W= 5.4 x 10⁷ -  2.5 x 10⁵  x 90 J

W= (540 - 25 x 9) 10⁵ J

W=315 x 10⁵ J

5 0
3 years ago
A 1150 kg pile driver is used to drive a steel I-beam into the ground. The pile driver falls 7.69 m before contacting the beam,
Natasha_Volkova [10]

Answer:

the average force 11226 N  

Explanation:

Let's analyze the problem we are asked for the average force, during the crash, we can find this from the impulse-momentum equation, but this equation needs the speeds and times of the crash that we could look for by kinematics.

Let's start looking for the stack speeds, it has a free fall, from rest  (Vo=0)

             

           Vf² = Vo² - 2gY

            Vf² = 0 - 2 9.8 7.69 = 150.7

            Vf = 12.3 m / s

This is the speed that the battery likes when it touches the beam.  They also give us the distance it travels before stopping, let's calculate the time

         

            Vf = Vo - g t

             0 = Vo - g t

             t = Vo / g

             t = 12.3 / 9.8

             t = 1.26 s

This is the time to stop

Now let's use the equation that relates the impulse to the amount of movement

                 I = Δp

                F t = pf-po

The amount of final movement is zero because the system stops

                F = - po / t

                F = - mv / t

                F = - 1150 12.3 / 1.26

                F = -11226 N

This is the average force exerted by the stack on the vean

7 0
3 years ago
The graph shows the number of beans eaten by a
il63 [147K]

Answer:

You didn't show a graph

Explanation:

6 0
4 years ago
Read 2 more answers
Which of the following can be explained with science? A.Plant growth B.Career options C.Moral value D.Meaning of life
Mnenie [13.5K]
The answer is A. Plant growth, Plant growth is the only thing that can actually be tested and scientificly measured, hope this helps!!!!
4 0
3 years ago
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