Need help true or false ? ECON

A minivan is tested for acceleration and braking. In the street-start acceleration test, the elapsed time is 8.6 s for a velocit

Varvara68 [4.7K]

The question is incomplete. Here is the complete question:

A minivan is tested for acceleration and braking. In the street-start acceleration test, the elapsed time is 8.6 s for a velocity increase from 10 km/h to 100 km/h. In the braking test, the distance traveled is 44 m during braking to a stop from 100 km/h. Assume constant values of acceleration and deceleration. Determine

(a) the acceleration during the street-start test,

(b) the deceleration during the braking test.

Answer:

(a) 37500 km/h²

(b) 113636.36 km/h²

Explanation:

part (a)

Because it is given that we can assume constant acceleration therefore we can use the following equation of motion:

v = u + (a)(t)

where v is final velocity, u is initial velocity, a is acceleration and t is time change

Given in the question:

v = 100km/h

u = 10 km/h

t = 8.6 sec (changing to hours)

t = 0.0024 hours (round off to 4 decimal places)

100 = 10 + (a x 0.0024)

Rearranging the equation to find value of a

a = (100 – 10) / 0.0024

a = 37500 km/h² (Answer)

part (b)

Now we can use the following equation to find deceleration

2(a)(s) = v² – u²

Where a is acceleration, s is distance travelled, v is final velocity and u is initial velocity

Given in the question

s = 44 m

changing to km

s = 0.044 km

v = 0 km/h (because it stops)

u = 100 km/h

2(a)(0.044) = (0)² – (100)²

0.088(a) = 0 - 10000

a = - 10000/0.088

a = - 113636.36 km/h2

The negative sign in the answer shows that it is deceleration

Therefore deceleration = 113636.36 km/h² (Answer)

6 0

3 years ago

A 2 N and an 8 N force pull on an object to the right and a 4 N force pulls on the same object to the left. If the object has a

Elden [556K]

Answer:

a = 12 [m/s²]

Explanation:

To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.

ΣF = m*a

where:

ΣF = sum of forces acting on a body [N] (units of Newtons)

m = mass = 0.5 [kg]

a = acceleration [m/s²]

Let's take the direction of positive forces to the right and negative forces directed to the left

2 + 8 - 4 = 0.5*a

6 = 0.5*a

a = 12 [m/s²]

7 0

3 years ago

Two speakers are spaced 15 m apart and are both producing an identical sound wave. You are standing at a spot as pictured. What

IgorLugansk [536]

Answer:

Frequency is $213.04\ s^{-1}.$

Explanation:

Distance between source 1 from the receiver , $S_1 =\sqrt{10^2+22^2}=24.17\ m.$

Distance between source 2 from the receiver , $S_2=\sqrt{5^2+22^2}=22.56\ m.$

Now ,

Path difference , $r = S_1-S_2=24.17-22.56=1.61\ m.$

We know, for constructive interference path difference should be integral multiple of wavelength .

Therefore, $r=n\times \lambda$

It is given that n = 1,

Therefore, $\lambda=1.61\ m.$

Frequency can be found by , $\nu=\dfrac{v}{\lambda}= \dfrac{343}{1.61}= 213.04\ s^{-1} .$

Hence, this is the required solution.

5 0

3 years ago

Often times we think about insulation, we think about keeping cold items cold, such as drinks in an ice chest or the cool temper

Burka [1]

Answer:

So, insulation essentially works by creating a sort of barrier between the hot and the cold object. This barrier helps to reduce heat transfer by either reflecting the thermal radiation or by decreasing thermal conduction and convection from one object to the other.

4 0

2 years ago

The number of electrons an atom would gain or lose when forming ionic bonds. It can be positive, negative or zero.

vaieri [72.5K]

Answer:

In an ionic bond , an element will have to lose or gain electrons.

Explanation:

Ionic bond, also called electrovalent bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound.
Such a bond forms when the valence (outermost) electrons of one atom are transferred permanently to another atom.
The atom that loses the electrons becomes a positively charged ion (cation), while the one that gains them becomes a negatively charged ion (anion).

∴

The number of electrons an atom would gain or lose when forming ionic bonds cannot be zero.

8 0

3 years ago