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LenaWriter [7]
3 years ago
14

An athlete whose mass is 87.0 kg is performing weight-lifting exercises. Starting from the rest position, he lifts, with constan

t acceleration, a barbell that weighs 600 N. He lifts the barbell a distance of 0.65 m in a time of 1.3 s. Use Newton's laws to find the total force that his feet exert on the ground as he lifts the barbell.
Physics
1 answer:
expeople1 [14]3 years ago
6 0

Answer: X = 52,314.12 N

Explanation: Let X be the force the feet of the athlete exerts on the floor.

According to newton's third law of motion the floor gives an upward reaction based on the weight of the athlete and the barbell which is known as the normal reaction ( based on the mass of the athlete and the barbell)

Mass of athlete = 87kg, mass of barbell = 600/ hence total normal reaction from the floor = 87* 61.22/ 9.8 *9.8 = 52,200N.

The athlete lifts the barbell from rest thus making it initial velocity u=0, distance covered = S = 0.65m and the time taken = 1.3s

The acceleration of the barbell is gotten by using the equation of constant acceleration motion

S= ut + 1/2at²

But u = 0

S = 1/2at²

0.65 = 1/2 *a (1.3)²

0.65 = 1.69 * a/2

0.65 * 2 = 1.69 * a

a = 0.65 * 2/ 1.69

a = 0.77m/s²

According to newton's second law of motion

Resultant force = mass * acceleration

And resultant force in this case is

X - 52,200 = (87 + 61.22) * 0.77

X - 52,200 = 148.22 * 0.77

X - 52, 200 = 114.132

X = 114.132 + 52,200

X = 52,314.12 N

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Answer:

Explanation:

distance of shuttle from centre of the earth = radius of the orbit

= 6300 + 300 = 6600 km

= 6600 x 10³

Formula of time period of the satellite

T = 2π R /v₀ , v₀ is orbital velocity

v₀ = √gR , ( if height  is small with respect to radius )

T = 2π R /√gR

= 2π√ R /√g

= 2 x 3.14 x √ 6600 x 10³ / √9.8

= 2 x 3.14 x 256.9 x 10 / 3.13

= 5154.41 s

= 5154.41 / 60 minutes

= 85.91 m

85.9 minutes.

2 ) No of sunrise per day = no of rotation per day

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= 16.76

or 17 sunrises.

3 0
3 years ago
A 10 m long clothesline is strung so that it is perfectly horizontal. when a shirt is hung in the exact center the line sags to
Leto [7]

Answer:

x = 0.0873 m

Explanation:

given,

length of clothesline = 10 m

the line sags to create an angle that is 1 degree below the horizontal on each end.

As mass is hang at the center the angle made let the deflection be 'x'

as the shirt is hang at the center distance will be equal to 5 m.

now

tan \theta = \dfrac{d_e}{d}

tan \theta = \dfrac{x}{5}

tan 1^0 = \dfrac{W}{5}

W = 5 \times 0.0175

x = 0.0873 m

Hence, the cloth line will be x = 0.0873 m from the original length of the clothesline.

3 0
3 years ago
The four major Earth systems are the atmosphere, lithosphere, hydrosphere, and geosphere. true and false
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2 years ago
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A kangaroo jumps straight up with an initial vertical velocity of 2.4m/s. We want to find the maximum height of the jump. We can
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Answer:

v  

2

=v  

0

2

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+2aΔxv, squared, equals, v, start subscript, 0, end subscript, squared, plus, 2, a, delta, x

Explanation:

8 0
2 years ago
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PLS ANSWER ASAP
vivado [14]

Answer:

Cart A

Explanation:

Momentum can be computed by finding the product of mass and velocity. To solve this, you can use the formula below to find the greatest momentum:

p = mv

where:

p = momentum (kgm/s)       m = mass (kg)         v = velocity (m/s)

Because carts are moving along with the weights, we need to consider the whole system. This means that you need to add in the masses and the mass of the cart.

<u>Cart A:</u>

m = 200kg + 0 kg = 200 kg

v = 4.8 m/s

p = 200kg x 4.8 m/s = 960 kg-m/s

<u>Cart B:</u>

m = 200kg + 20 kg = 220 kg

v = 4.0 m/s

p = 220kg x 4.0 m/s = 880 kg-m/s

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v = 3.8 m/s

p = 240kg x 3.8 m/s = 912 kg-m/s

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p = 260kg x 3.5 m/s = 910 kg-m/s

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