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alukav5142 [94]
3 years ago
5

A long distance runner running a 5.0km track is pacing himself by running 4.5km at 9.0km/h and the rest at 12.5km/h. What is his

average speed?
Physics
1 answer:
sweet [91]3 years ago
6 0

Answer:

9.26 km/h

Explanation:

Applying,

V' = D'/t'............... Equation 1

Where V' = Average speed, D' = Total distance, t' = total time.

Given: D' = 5 km

But,

v = d/t............ Equation 2

Where v = speed , d = distance, t = time

t = d/v............ Equation 3

Given: d = 4.5 km, v = 9 km/h, and d = 0.5 km, v = 12.5 km/h

Therefore,

t₁ = 4.5/9 = 0.5 hours

t₂ = 0.5/12.5

t₂ = 0.04 hours

Therefore,

V' = 5/(0.5+0.04)

V' = 5/0.54

V' = 9.26 km/h

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A 100.0-kg bakery sign hangs from two thin cables as shown.
harina [27]

Answer:

1. T₁ = 500 N

2. T₂ = 866 N

Explanation:

Please see attached photo for the diagram.

Thus, we can obtain obtained the value of T₁ and T₂ as follow:

1. Determination of T₁

Angle θ = 30

Hypothenus = 100 kg

Opposite = T₁ =?

Sine θ = Opposite /Hypothenus

Sine 30 = T₁ / 100

Cross multiply

T₁ = 100 × Sine 30

T₁ = 100 × 0.5

T₁ = 50 Kg

Multiply by 10 to express in Newton

T₁ = 50 × 10

T₁ = 500 N

2. Determination of T₂

Angle θ = 60

Hypothenus = 100 kg

Opposite = T₂ = ?

Sine θ = Opposite /Hypothenus

Sine 60 = T₂ / 100

Cross multiply

T₂ = 100 × Sine 60

T₂ = 100 × 0.8660

T₂ = 86.6 Kg

Multiply by 10 to express in Newton

T₂ = 86.6 × 10

T₂ = 866 N

5 0
3 years ago
a crate is lifted vertically 1.5 m and then held at rest. the crate has weight 100 n (i.e., it is supported by an upward force o
san4es73 [151]

The required work to hold the crate above the ground is 150 joule.

We need to know about the work done to solve this problem. The work done by an object depends on the force applied and the distance. The work is proportional to force and displacement. It can be written as

W = F . s

where W is work done, F is the force and s is displacement

From the question above, the given parameters are

F = 100 N

s = 1.5

Thus, the required work to hold the crate above the ground can be calculated

W = F . s

W = 100 . 1.5

W = 150 joule

Find more on work at: brainly.com/question/25573309

#SPJ4

6 0
1 year ago
Suppose you place a ball in the middle of a wagon, and then accelerate the wagon forward. Describe the motion of the ball relati
rjkz [21]

Answer:

The motion of the ball relative to the ground is stationary

The motion of the ball relative to the wagon is backwards

Explanation:

To describe the motion of the ball relative to the ground, we note that

Assuming the ball is perfectly round and rotate freely, then we have

Force on the ball due to motion of the wagon = 0 N,

Then by the law of motion, an object will remain at rest when no force is applied to it

Therefore, apart from rotation of the ball, it will remain no displacement relative to the ground.

The motion of the ball relative to the wagon

Relative to the wagon, the ball appears to be moving in the opposite direction to the wagon, that is backwards.

4 0
3 years ago
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If the mass of an object is cut in half how does the kinetic energry change\
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I believe that the less mass/weight there is the least friction there is.
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A transformer has 100 turns in its primary coil and 75 turns in its secondary coil. If the input voltage is 12.0 V, what is the
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Is 54 por que es igual
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