A 20kg bike accelerates at 10 m/s2. With what force was the person padeling?

Tourists covered 255 km for a 4-hour ride by car and a 7-hour ride by train. what is the speed of the train, if it is 5 km/h gre

LekaFEV [45]

The distance covered by car is equal to (assuming it is moving by uniform motion) the product between the car's speed and the time of the car ride, 4 h:
$S_c = v_c t_c$
where
$v_c$ is the car's speed
$t_c = 4 h$ is the duration of the car ride

Similarly, the distance covered by train is equal to the product between the train's speed and the duration of the train ride, 7 h:
$S_t = v_t t_t$

The total distance covered is S=255 km, which is the sum of the distances covered by car and train:
$S=255 km = S_c + S_t$
which becomes
$255 = 4 v_c + 7 v_t$ (1)
we also know that the train speed is 5 km/h greater than the car's speed:
$v_t = 5 + v_c$ (2)

If we put (2) into (1), we find
$255 = 4v_c + 7(5+v_c)$
and if we solve it, we find
$v_c = 20 km/h$
$v_t = 25 km/h$

So, the car speed is 20 km/h and the train speed is 25 km/h.

4 0

3 years ago

The gage pressure in a liquid at a depth of 3 m is read to be 39 kPa. Determine the gage pressure in the same liquid at a depth

ioda

Answer: 117 kPa

Explanation:

For the liquid at depth 3 m, the gauge pressure is equal to = P₁=39 kPa

For the liquid at depth 9m, the gauge pressure is equal to= P₂

Now we are given the condition that the liquid is same. That must imply that the density must be same throughout the depth.

So, For finding gauge pressure we have formula P= ρ * g * h

Also gravity also remains same for both liquids

So taking ratio of their respective pressures we have

$\frac{P_{1} }{\\P_2}$ = $\frac{density * g * h_1}{density * g * h_2}$

So $\frac{39}{P_2}$ = $\frac{3}{9}$

Or P₂= 39 * 3 = 117 kPa

5 0

3 years ago

Helpppppppppppppppppppppppppppopppppppppp

harkovskaia [24]

Answer:

I think it's 2 the photo is hard to tell what they are exactly talking about.

7 0

3 years ago

Several short trips taken from a cold start can use ....... as much fuel as a longer multi-purpose trip covering the same distan

Lerok [7]

Several short trips taken from a cold start can use ...twice... as much fuel as a longer multi-purpose trip covering the same distance when the engine is warm.

In cold weather, properly designed gasoline aids in engine starting, while in hot weather, it helps prevent vapor lock. In order to meet the requirements of a modern engine, the fuel must have the volatility for which the engine's fuel system was built and an antiknock quality strong enough to prevent knock during routine operation.

During the intake phase, the air and fuel are combined before being introduced into the cylinder. The spark ignites the fuel-air mixture after the piston compresses it, resulting in combustion. During the power stroke, the piston is propelled by the expansion of the combustion gases.

To learn more about engine and fuel please visit -
brainly.com/question/5181209
#SPJ4

4 0

2 years ago

3.

lozanna [386]

The force of gravity produces acceleration in all C. freely falling objects and this is known as acceleration due to gravity

Explanation:

A body is said to be in free fall when there is only one force acting on the body: the force of gravity.

Gravity is a force that acts downward, i.e. towards the Earth's centre.

If we are near the Earth's surface, the magnitude of the force of gravity on a body is given by

$F=mg$

where:

m is the mass of the body

g is known as the acceleration of gravity , whose value near the Earth's surface is $9.8 m/s^2$ ).

We can apply Newton's second law on an object in free-fall, to find its acceleration. In fact, we have:

$F=ma$

where F is the force acting on the body and a is its acceleration.

Solving for the acceleration,

$a=\frac{F}{m}$

And substituting F,

$a=\frac{mg}{m}=g=9.8 m/s^2$

Therefore, every object in free-fall accelerates at $9.8 m/s^2$ towards the ground.

Learn more about free fall here:

brainly.com/question/1748290

brainly.com/question/11042118

brainly.com/question/2455974

brainly.com/question/2607086

#LearnwithBrainly

8 0

3 years ago