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2 years ago

A boy jumps from a wall 3m high. What is an estimate of the change in momentum of the boy when he lands without rebounding?

Physics

1 answer:

EastWind [94]2 years ago

8 0

The answer is D. Because the boy jump 3 high

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the picture below shows two parallel wires carrying current in the same direction. what is the net force on wire 2 due to wire 1

erastovalidia [21]

Answer:

I dont see a picture where is it?

Explanation:

I cannot see anything L question Luestion

3 0

1 year ago

A box exerts 10,000 Pa of pressure on the ground. If the box weighs 1000 N, how much area is in contact with the ground?

lara [203]

Pressure = (total force) / (Area)

10,000 Pa = (1,000 N) / (Area)

Multiply each side by (Area) :

(10,000 Pa) x (Area) = 1,000 N

Divide each side by (10,000 Pa) :

Area = (1,000 N) / (10,000 Pa)

4 0

2 years ago

The oxygen in earth’s atmosphere is a product of what?

Nina [5.8K]

Answer:

The answer is tiny organisms known as cyanobacteria, or blue-green algae. These microbes conduct photosynthesis: using sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen.

7 0

2 years ago

You have your bicycle upside down for repairs, with is 66.0 cm diameter wheel spinning freely at 230 rpm. The wheel's mass is 1.

rosijanka [135]

Answer:

$\omega_f = 17.86\ rad/s$

Explanation:

given,

dia of wheel = 66 cm

radius = 33 cm = 0.33 m

mass of wheel = 1.90 Kg

speed of wheel = 230 rpm

time to hold the tire = 3.10 s

Normal force = 2.7 N

coefficient of friction = 0.46

final angular speed = ?

we know

F = μ N

F = 0.46 x 2.7 = 1.242 N

torque

τ = F r

τ = 1.242 x 0.33 = 0.409 Nm

moment of inertia for wheel

I = MR²

I = 1.90 x 0.33²

I = 0.2069 kg m²

we now,

τ = I x α

$\alpha = \dfrac{\tau}{I}$

$\alpha = \dfrac{0.409}{0.2069}$

α = 1.981 rad/s²

we know,

$\omega_f - \omega_i = \alpha\ t$

$\omega_f - (230\dfrac{2\pi}{60}) =- 1.981 \times 3.1$

$\omega_f - 24 = - 6.14$

$\omega_f = 17.86\ rad/s$

7 0

2 years ago

In the figure below, a block of 1.67 slides on a track with different levels, which has friction only at the highest point where

Natasha_Volkova [10]

Answer:

2.0 m

Explanation:

Energy is conserved.

Initial KE = Final PE + Work done by friction

½ mv² = mgh + Fd

½ mv² = mgh + mgμd

½ v² = gh + gμd

½ v² − gh = gμd

d = (½ v² − gh) / (gμ)

d = (½ (7.5 m/s)² − (10 m/s²) (2.1 m)) / ((10 m/s²) (0.35))

d = 2.0 m

7 0

3 years ago