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3 years ago

A car enters a tunnel at 24 m/s and accelerates steadily at 2.0 m/s2. At what speed does it leave the tunnel, 8.0 seconds later?

1 answer:

4 0

Given:

V1 = initial velocity = 24 m/s
a = acceleration = 2.0 m/s^2
s = time = 8 s
V2 = final velocity = ?

For linear-motion problems with those given terms, the following formula is used:

V2 = V1 + as

Substituting the given values:

V2 = 24 + 2(8)
V2 = 24 + 16
V2 = 40 m/s

Therefore the car will have a speed of 40 m/s as it leaves the tunnel.

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How much heat is needed to raise the temperature of 2 kg of copper from 20º to 30ºC. The specific heat of copper is 390 J/kgºC.

ryzh [129]

Answer:

7800 J

Explanation:

Heat needed = mass of copper x specific heat of copper x change in temperature

Change in temperature = 30ºC - 20ºC = 10ºC

Specific heat of copper = 390 J/kgºC

Mass of copper = 2 Kg

Substituting the given values in above equation, we get –

Heat needed = 2 Kg x 390 J/kgºC x 10ºC

= 7800 J

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3 years ago

Objects 1 and 2 attract each other with a electrostatic force

algol13

Answer:

72.0 + 72.0 whatever you get for that answer

Explanation:

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2 years ago

An archer defending a castle is on a 15.5 m high wall. He shoots an arrow straight down at 22.8 m/s. How much time does it take

vazorg [7]

Answer: 1.907

Explanation:

I did the math

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4 years ago

A cheetah can accelerate from rest at the rate of 4m /s

lesya [120]

Acceleration of cheetah (a) = 4m/s²
time = 10s
initial velocity(u) = 0
final velocity = v
distance travelled = s

v = u +at = 0 + 10×4 = 40m/s
s = (v²-u²)/2a = 40²/(2×4) = 1600/8 = 200m

6 0

3 years ago

Jada is rowing a boat across a river that has a current of 5 m/s in the ˆ j direction. Leanne, standing on the shore, observes J

olchik [2.2K]

Answer: d. 8.25 m/s

Explanation:

We are given that Current= 5 m/s in j direction

Velocity= 8 m/s i + 3 m/s j

Now, we have to find Jada's speed with respect to the water.

First we find Jada's velocity with respect to water

v= (8 i + 3 j) - (5 j)

v= 8i - 2 j

To find the speed, we take the magnitude of this velocity vector we have

|v|= $\sqrt{(8)^2+(-2)^2}$

|v|= $\sqrt{68}$ = 8.246 m/s

which comes out to be around = 8.25 m/s

So option d is correct.

5 0

3 years ago