Someone please help me!

A car with a mass of 1,000 kg moving with an initial velocity of 8 m/s is brought to rest by colliding with a truck. The collisi

ruslelena [56]

Answer:

-40,000 N

Explanation:

First, use the kinematics equation v(f) = v(i) + at. Final velocity is 0, initial is 8, and time is 0.2 seconds. Solving for a, you get -40 m/s^2. Then, use Newton’s second law, F=ma, to find the force. F = (1000)(-40) = -40,000 N.

4 0

4 years ago

A hockey player strikes a puck, giving it an initial velocity of 14.0 m/s in the positive x-direction. The puck slows uniformly

Advocard [28]

a) $-1.71 m/s^2$

b) 7.7 m/s

c) 4.39 s

Explanation:

a)

The acceleration of an object is the rate of change of velocity of an object.

In this problem, the acceleration of the puck can be found using the following suvat equation:

$v^2-u^2=2as$

where:

v is the final velocity

u is the initial velocity

a is the acceleration

s is the distance travelled

For the puck in this problem:

u = 14.0 m/s

v = 6.50 m/s

s = 45.0 m

So, the acceleration is:

$a=\frac{v^2-u^2}{2s}=\frac{6.50^2-14.0^2}{2(45.0)}=-1.71 m/s^2$

b)

The velocity of the puck at time t can be found by using another suvat equation:

$v=u+at$

where

u is the initial velocity

a is the acceleration

t is the time elapsed

v is the final velocity

Here, we have:

u = 14.0 m/s

$a=-1.71 m/s^2$ (found in part a)

Therefore, the velocity of the puck after t = 3.70 s is:

$v=14.0+(-1.71)(3.70)=7.7 m/s$

c)

Here we want to find the time taken for the puck to travel a distance of

s = 45.0 m

To solve this part, we can use again the suvat equation:

$v=u+at$

Where in this case, we use:

u = 14.0 m/s is the initial velocity

v = 6.50 m/s is the final velocity when the puck has travelled 45.0 m (this information is given in the question)

$a=-1.71 m/s^2$ is the acceleration (found in part a)

Therefore, by re-arranging the equation, we find the time taken to cover 45.0 m:

$t=\frac{v-u}{a}=\frac{6.50-14.0}{-1.71}=4.39 s$

7 0

3 years ago

A 75.5-kg person puts on a life jacket, jumps into the water, and floats. The jacket has a volume of 3.38 x 10-2 m3 and is compl

Andreyy89

Answer:

Density of jacket will be $680.4733kg/m^3$

Explanation:

We know that weight of water displaced= buoyant force=weight of man

Now volume of water displaced $v=3.38\times 10^{-2}+6.42\times 10^{-2}=9.8\times 10^{-2}m^3$

Density of water $d=100kg/m^3$

So weight of water displaced $=9.8\times 10^{-2}\times 1000=98kg$

So weight of jacket = 98-75 = 23 kg

We have given volume of the jacket = $3.38\times 10^{-2}m^3$

So density of jacket $=\frac{mass}{volume}=\frac{23}{3.38\times 10^{-2}}=680.4733kg/m^3$

6 0

3 years ago

Please help me!! I already did A,B and C but I don’t know D but if you want to help me with all then it would be great so I can

Inessa [10]

Answer:

350cm^3 =350milliters

4 0

3 years ago

Read 2 more answers

You drive a car for 2.0 h at 60 km/h, then for another 3.0 h at 85 km/h. What is your average velocity

Anon25 [30]

Answer:

Explanation:

Average velocity is found in the total displacement experienced in the trip divided by the total time it took to make this trip. If, for the first 2.0 hours, the car travels at 60 km/hr, then in 2.0 hours the car can travel 120 km; if it then travels for 3.0 at 85 km/hr, it can travel 255 km in the same direction. The total time this took was 5.0 hours. So doing the math and rounding correctly by following the rules for the adding and subtracting of sig fig's:

$v=\frac{120+255}{5.0}=\frac{380}{5.0}=76\frac{km}{hr}$

If you do not round when you add, the average velocity is 75 km/hr

8 0

3 years ago