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2 years ago

7

A crate is sliding on the floor. If there is a total force acting on the crate in the same direction as it is sliding, the crate

would
A) slow down
B) speed up
C) remains the same speed
D) slow down, change direction and then speed up going the other way,
E) remains the same speed but changes direction

1 answer:

Leto [7]2 years ago

7 0

But we do not know whether the force is pushing or pulling (the same direction (both forces are parallel) but: .........[ ]<-F-- or .......[ ]--F-->). I suppose the correct answer is B

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A compact car has a mass of 1380 kg . Assume that the car has one spring on each wheel, that the springs are identical, and that

astraxan [27]

Answer:

A) $k=34867.3384\ N.m^{-1}$

B) $\omega'\approx84\ Hz$

Explanation:

Given:

mass of car, $m=1380\ kg$

A)

frequency of spring oscillation, $f=1.6\ Hz$

We knkow the formula for spring oscillation frequency:

$\omega=2\pi.f$

$\Rightarrow \sqrt{\frac{k_{eq}}{m} } =2\pi.f$

$\sqrt{\frac{k_{eq}}{1380} } =2\times \pi\times 1.6$

$k_{eq}=139469.3537\ N.m^{-1}$

Now as we know that the springs are in parallel and their stiffness constant gets added up in parallel.

<u>So, the stiffness of each spring is (as they are identical):</u>

$k=\frac{k_{eq}}{4}$

$k=\frac{139469.3537}{4}$

$k=34867.3384\ N.m^{-1}$

B)

given that 4 passengers of mass 70 kg each are in the car, then the oscillation frequency:

$\omega'=\sqrt{\frac{k_{eq}}{(m+70\times 4)} }$

$\omega'=\sqrt{\frac{139469.3537}{(1380+280)} }$

$\omega'\approx84\ Hz$

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3 years ago

What are the units of radiation?

Ksenya-84 [330]

The radiation dose absorbed by a person is measured using the conventional unit rad or the SI unit gray. The biological risk of exposure to radiation is measured using the conventional unit rem or the SI unit sievert.

I hope this helps!

3 0

2 years ago

Severus Snape knows that density of his powder is 3.00 g/cm3 . He also knows he needs 3.00 cm3 of this powder. What mass in gram

harina [27]

Answer:

He requires 1 gram of mass.

Explanation:

The density is defined as:

$\rho = \frac{m}{V}$ (1)

Where m is the mass and V is the volume.

Then, m can be isolated from equation 1 in order to determine the mass.

$m = \rho \cdot V$ (2)

$m = (3.00g/cm^{3})(3.00cm^{3})$

$m = 1g$

Hence, he requires 1 gram of mass.

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3 years ago

Un dulap are laturile de jos egale cu 60cm si1,1m,iar masa lui este de 25kg.Ce presiune exercita dulapul asupra podelei? URGENT!

Tcecarenko [31]

Answer:

okkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk

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2 years ago

A proton traveling with speed 2 × 105 m/s in the -y direction passes through a region in which there is a uniform magnetic field

stepladder [879]

Answer:

$\vec{E} = 1.2\times 10^5(-i)$

Explanation:

Given that

Speed ,v= 2 x 10⁵ m/s ( - y direction)

B= 0.6 T (- z direction)

The resultant force on the proton given as

$\vec{F}=q.\vec{E}+ q.(\vec{v}\times \vec{B})$

F= m a

For uniform motion acceleration should be zero.

F = 0

$0=q.\vec{E}+ q.(\vec{v}\times \vec{B})$

$0=\vec{E}+ (\vec{v}\times \vec{B})$

$0=\vec{E}+2\times 10^5(-j) \times 0.6(-k)$

$\vec{E} =- 2\times 10^5(-j) \times 0.6(-k)$

$\vec{E} =-1.2\times 10^5(i)$

$\vec{E} = 1.2\times 10^5(-i)$

Electric filed should be apply in the negative x direction.

5 0

2 years ago