Ask question

Ask question

All categories

3 years ago

7

Two cars collide on the parkway. The drivers are following too closely and the driver in the front slows because of traffic to a

velocity of 20.0m/s and the driver behind is still moving at 30.0m/s, both cars traveling in the same direction in a rear end collision. If the cars are stuck together after the collision, how fast will they be traveling?

1 answer:

musickatia [10]3 years ago

4 0

Answer:

The are moving with a speed of 25 m/s after the collision.

Explanation:

assuming the mass (m) of the cars are equal, let v = 20 m/s be the velocity of the driver in the front and u = 30 m/s be the velocity of the driver behind. let V be the velocity of the cars after the collision.

then, by conservation of linear momentum:

m×(v + u) = V×2×m

(v + u) = V×2

V = (v + u)/2

= (20 + 30)/2

= 25 m/s

Therefore, the are moving with a speed of 25 m/s after the collision.

You might be interested in

Several large firecrackers are inserted into the holes of a bowling ball, and the 6.3 kg ball is then launched into the air with

Anni [7]

Answer

given,

mass of the ball = 6.3 kg

speed of the ball = 10.4 m/s

angle made with horizontal = 43°

m_a = 1.8 kg v_a = 2.2 m/s

m_b = 1.6 kg v_b = 1.8 m/s

mass of third particle = 6.3 - 1.8 - 1.6

= 2.9 kg

u cos θ = 10.4 x cos 43° = 7.61 m/s

by using conservation momentum along x-axis

6.3 x 7.61 = 1.8 × (-2.2) + 0 + 1.6 × V₃ₓ

V₃ₓ = 32.44 m/s (toward right)

by using conservation momentum along y-axis

0 = 0 + 1.6 x 1.8 + 1.6 × V₃y

V₃y = -1.8 m/s (indicate downward)

velocity of the third particle

$v = \sqrt{32.44^2 + (-1.8)^2}$

v = 32.49 m/s

$tan \theta = \dfrac{-1.8}{32.44}$

$\theta = tan^{-1}(\dfrac{-1.8}{32.44})$

θ = 3.176° (downward with horizontal)

4 0

3 years ago

5. A sled with no initial velocity accelerates at a rate of 5.0 m/s2 down a hill. How

ad-work [718]

Answer:

60 m/s

Explanation:

$a = \frac{vf - vi}{t}$

$5.0 = \frac{vf - 0}{12}$

$5.0 \times 12 = vf$

$60 = vf$

6 0

3 years ago

The measure of how much salt will dissolve into 100g of water is _______________ .

Bingel [31]

The measure of how much salt will dissolve into 100g of water is _solution_ .

8 0

3 years ago

Read 2 more answers

A uniform magnetic field is perpendicular to the plane of a circular loop of diameter 13 cm formed from wire of diameter 2.6 mm

I am Lyosha [343]

Answer:

Rate of change of magnetic field is $3.466\times 10^3T/sec$

Explanation:

We have given diameter of the circular loop is 13 cm = 0.13 m

So radius of the circular loop $r=\frac{0.13}{2}=0.065m$

Length of the circular loop $L=2\pi r=2\times 3.14\times 0.065=0.4082m$

Wire is made up of diameter of 2.6 mm

So radius $r=\frac{2.6}{2}=1.3mm=0.0013m$

Cross sectional area of wire $A=\pi r^2=3.14\times0.0013^2=5.30\times 10^{-6}m^2$

Resistivity of wire $\rho =2.18\times 10^{-8}m$

Resistance of wire $R=\frac{\rho L}{A}=\frac{2.18\times 10^{-8}\times 0.4082}{5.30\times 10^{-6}}=1.67\times 10^{-3}ohm$

Current is given i = 11 A

So emf $e=11\times 1.67\times 10^{-3}=0.0183volt$

Emf induced in the coil is $e=-\frac{d\Phi }{dt}=-A\frac{dB}{dt}$

$0.0183=5.30\times 10^{-6}\times \frac{dB}{dt}$

$\frac{dB}{dt}=3.466\times 10^3=T/sec$

8 0

3 years ago

A block of ice with mass 2.00 kg slides 0.750 m down an inclined plane that slopes downward at an angle of 36.9 degrees below th

zhannawk [14.2K]

Answer: $V_{f}=2.96m/s$

Firstly we have to draw the Free Body Diagram (FBD) as shown in the figure attached.

Where the weight $w$ of the block has an x-component and y-component:

$w_{x}=wsin(\theta)$ (1)

$w_{y}=wcos(\theta)$ (2)

As well as the Normal Force $N$ :

$N_{x}=Nsin(\theta)$ (3)

$N_{y}=Ncos(\theta)$ (4)

In addition, we know $N=w$ , then $\sum F_{y}=0$

In the X-component:

$\sum F_{x}=m.a$

$m.a=w_{x}$ (5)

Substituting (1) in (5):

$wsin(\theta)=m.a$ (6)

In addition, we know $w=m.g$ , where $m$ is the mass of the block and $g$ the gravity acceleration, which is equal to $9.8m/{s}^{2}$

So:

$m.g.sin(\theta)=m.a$ (7)

$a=g.sin(\theta)$ (8)

$a=5.88m/{s}^{2}$ (9) >>>>This is the acceleration of the block

On the other hand, we have the following equation that expresses a <u>relation between</u> the distance $d$ with the acceleration $a$ and time $t$ :

$d=\frac{1}{2}a{t}^{2}$ (10)

We already know the value of $d$ and calculated $a$ , we have to find $t$ :

$t=\sqrt{\frac{2d}{a}}$ (11)

$t=\sqrt{\frac{2(0.75m)}{5.88m/{s}^{2}}}$ (12)

$t=0.50s$ (13) >>>This is the time it takes to the block to go from the initial velocity $V_{o}$ to its final velocity $V_{f}$

If the acceleration is the variation of the velocity in time, we can use the following equation to find $V_{f}$ :

$V_{f}-V_{o}=a.t$ (13)

If $V_{o}=0$

$V_{f}=a.t$ (14)

$V_{f}=(5.88m/{s}^{2})(0.50s)$ (15)

Finally we get the value of the Final Velocity of the block:

$V_{f}=2.96m/s$

6 0

3 years ago