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4 years ago

Why does metal feel colder than cardboard? Enter in complete sentences

1 answer:

6 0

<span>For any object to feel cold, it must be colder than your hand. Cardboard is made of materials that do not hold in coldness that we feel. However, metal absorbs the cold, and thus we feel the temperature because of the contrast of our body temperature.</span>

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As relay runner A enters the 65-ft-long exchange zone with a speed of 30 ft/s, he begins to slow down. He hands the baton to run

Hoochie [10]

Answer:

a_a = -3.2 ft/s^2 , a_b = 3.723 ft/s^2

t = 5.909 s

Explanation:

Given:

- Initial velocity of A v_i,a = 30 ft /s

- Initial distance s_o = 0

- Length of the exchange zone s_f = 65 ft

- Time taken t = 2.5 s

Start out by A's velocity as he gets to the end of the exchange zone.

Part a

Runner A decelerates at a uniform rate, so you can use the equation:

s_f = s_o + v_i,a*t + 0.5a_a*t^2

65 = 0 + 30*2.5 + 0.5*a_a*2.5^2

a_a = -20 / 2.5^2

a _a= -3.2 ft/s^2

Runner B accelerates at v_f,a as final velocity at a uniform rate, so you can use the equation:

v_f,b^2 - v_i,b^2 = 2*a_b*s

a_b = (30 -3.2*2.5)^2 /2*65

a_b = 3.723 ft/s^2

Part b

When Runner B should begin running:

t = (v_f,b - v_i,b) / a_b

t = (30 - 3.2*2.5) / 3.723

t = 5.909 s

5 0

3 years ago

For the ride to be comfortable, the magnitude of acceleration must not exceed 32 m/s2. What is the fastest constant speed that a

VMariaS [17]

Answer:

the maximum possible constant speed is 8 m/sec

Explanation:

from the image, Given that

r(t) = (2t, t²,t²/3), -5 ≤ t ≤ 5

Given that the curvature K(t) = 2 / ( t² + 2)²

note that t² + 2 ≥ 2

(t² + 2)² ≥ 4

1 / (t² + 2)² ≤ 1/4

2 / (t² + 2)² ≤ 1/2

Also note that k(0) = 1/2

The normal component of acceleration satisfies aN = kv²

where v = ║v(t)║is the speed of the roller coaster.

The maximum possible normal component of acceleration is 32

so, aN ≤ 32 every where on the track

aN = kv² ≤ 1/2v² ≤ 32

v² ≤ 64

Therefore, the maximum possible constant speed is 8 m/sec

7 0

3 years ago

One way to force air into an unconscious person's lungs is to squeeze on a balloon appropriately connected to the subject. What

frozen [14]

Answer:

The force that you must exert on the balloon is 1.96 N

Explanation:

Given;

height of water, h = 4.00 cm = 4 x 10⁻² m

effective area, A = 50.0 cm² = 50 x 10⁻⁴ m²

density of water, ρ = 1 x 10³ kg/m³

Gauge pressure of the balloon is calculated as;

P = ρgh

where;

ρ is density of water

g is acceleration due to gravity

h is height of water

P = 1 x 10³ x 9.8 x 4 x 10⁻²

P = 392 N/m²

The force exerted on the balloon is calculated as;

F = PA

where;

P is pressure of the balloon

A is the effective area

F = 392 x 50 x 10⁻⁴

F = 1.96 N

Therefore, the force that you must exert on the balloon is 1.96 N

3 0

4 years ago

A rocket is launched straight up with constant acceleration. Four seconds after liftoff, a bolt falls off the side of the rocket

Nadusha1986 [10]

Answer:

A rocket is launched straight up with constant acceleration. Four seconds after liftoff, a bolt falls off the side of the rocket. The bolt hits the ground 6.10s later.

Explanation:

A rocket is launched straight up with constant acceleration. Four seconds after liftoff, a bolt falls off the side of the rocket. The bolt hits the ground 6.0 s later. What was the rocket’s acceleration?

6 0

4 years ago

Giving me the points are enough <br>

N76 [4]

Answer:

the product of mass and velocity

....in my syllabus

7 0

3 years ago