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Which statement correctly describes the differences between positive and negative acceleration? Positive acceleration describes

qwelly [4]

The correct answer is - Positive acceleration describes an increase in speed; negative acceleration describes a decrease in speed.

4 0

3 years ago

Read 2 more answers

A 1500 kg car moving with a speed of 20 m/s collides with a utility pole and is brought to rest in 0.30 s. Find the magnitude of

storchak [24]

Answer:

-100000 N.

Explanation:

Force: This can be defined as the product of the mass of a body and it's acceleration. The S.I unit of Force is Newton(N). The Formula of force is given as,

F = ma ........................... Equation 1

Where F = Average force exerted on the car, m = mass of the car, acceleration of the car, a = acceleration of the car.

a = (v-u)/t..................... Equation 2

Where v = Final velocity, u = Initial velocity, t = time.

Substitute equation 2 into equation 1

F = m(v-u)/t............. Equation 3

Given: m = 1500 kg, u = 20 m/s, v = 0 m/s (brought to rest), t = 0.3 s.

Substitute into equation 3

F = 1500(0-20)/0.3

F = 1500(-20)/0.3

F = -100000 N.

Note: The negative sign is due to the fact that the force exerted on the car by the pole is equal and opposite the force of the car.

7 0

3 years ago

A mass of 148 g stretches a spring 13 cm. The mass is set in motion from its equlibrium position with a downward velocity of 10

Charra [1.4K]

Answer:

$u(t)=1.15 \sin (8.68t)cm$

0.3619sec

Explanation:

Given that

Mass,m=148 g

Length,L=13 cm

Velocity,u'(0)=10 cm/s

We have to find the position u of the mass at any time t

We know that

$\omega_0=\sqrt{\frac{g}{L}}\\\\=\sqrt{\frac{980}{13}}\\\\=8.68 rad/s$

Where $g=980 cm/s^2$

$u(t)=Acos8.68 t+Bsin 8.68t$

u(0)=0

Substitute the value

$A=0\\u'(t)=-8.68Asin8.68t+8.68 Bcos8.86 t$

Substitute u'(0)=10

$8.68B=10$

$B=\frac{10}{8.68}=1.15$

Substitute the values

$u(t)=1.15 \sin (8.68t)cm$

Period =T = 2π/8.68

After half period

π/8.68 it returns to equilibruim

π/8.68 = 0.3619sec

6 0

3 years ago

Which of these pairs of atoms are isotpoes? (Physical Science) Pair A Pair B Pair C # protons 6 8 5 2 12 12 # neutrons 8 8 5 3 1

Aleksandr-060686 [28]

Answer:

I guess that the atoms are:

Protons: 6 8 5 2 12 12

Neutrons: 8 8 5 3 13 14

Now, two atoms are isotopes if they share the same number of protons (so both atoms are the same element) but they have a different number of neutrons.

From the given options, the only two that have the same number of protons but a different number of neutrons are:

Protons 12, neutrons 13

and

Protons 12, neutrons 14.

These two are isiotopes.

4 0

2 years ago

the curiosity rover sent to explore the surface of mars has an electric generator powered by heat from the radioactive decay of

pav-90 [236]

An element can be identified by its unique atomic number. When we look in the periodic table, we find that the element with an atomic number of 9292 is uranium. There is only option containing uranium which also confirms the mass number we found. So, the daughter nucleus of the decay is 234^U.

In an alpha decay, a positively charged particle similar to a helium-4 nucleus gets released from the parent nucleus spontaneously. As the composition suggests, an alpha particle consists of two protons and 2 neutrons. The particle does not travel much, but in short range, it carries the most energy.

It's smart to use the thermal energy provided by the radioactive decay to generate electricity. This allows for a stable supply of power without consuming much space which means the saved space can be used for more scientific equipment. The alpha particle, structurally equivalent to the nucleus of a helium atom.

Learn more about nucleus here:

brainly.com/question/23366064

#SPJ4

3 0

1 year ago