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Sindrei [870]
2 years ago
14

If steel is more dense than lake water, why can a boat float?

Physics
2 answers:
Ivenika [448]2 years ago
7 0

The average density of the boat, including the steel and air, is less dense than 1.00 g/cm³.

Setler [38]2 years ago
4 0

Answer:

<h2><em><u>A </u></em></h2>

Explanation:

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Gibbons, small Asian apes, move by brachiation, swinging below a handhold to move forward to the next handhold. A 9.4 kg gibbon
Katarina [22]

Answer:

upward force acting = 261.6 N

Explanation:

given,

mass of gibbon = 9.4 kg

arm length = 0.6 m

speed of the swing

net force must provide

F_{branch} + F_{gravity}=F_{centripetal}

force of gravity = - mg

F_{branch}=F_{centripetal}-F_{gravity}

                        = \dfrac{mv^2}{r} + mg

                        = m(\dfrac{3.4^2}{0.6} +9.8)

                        =9 x 29.067

                        = 261.6 N

upward force acting = 261.6 N

7 0
3 years ago
The velocity - time graph of a ball of mass 25g moving on road is as given below:
Airida [17]
25g of mass will require 25g of opposite force on the ball from the road and opposition is moving upward to work on the ball 
4 0
3 years ago
Jumping up before the elevator hits. After the cable snaps and the safety system fails, an elevator cab free-falls from a height
noname [10]

Answer:

a)   I = 2279.5 N s , b) F = 3.80 10⁵ N, c)   I = 3125.5 N s  and d)  F = 5.21 10⁵ N

Explanation:

The impulse is equal to the variation in the amount of movement.

    I =∫ F dt = Δp

     I = mv_{f} - m v₀

Let's calculate the final speed using kinematics, as the cable breaks the initial speed is zero

   v_{f}² = V₀² - 2g y

   v_{f}² = 0 - 2 9.8 30.0

   v_{f} = √588

   v_{f} = 24.25 m/s

a) We calculate the impulse

   I = 94 24.25 - 0

   I = 2279.5 N s

b) Let's join the other expression of the impulse to calculate the average force

   I = F t

  F = I / t

  F = 2279.5 / 6 10⁻³

  F = 3.80 10⁵ N

just before the crash the passenger jumps up with v = 8 m / s, let's take the moments of interest just when the elevator arrives with a speed of 24.25m/s down and as an end point the jump up to vf = 8 m / n

c)     I = m v_{f} - m v₀

       I = 94 8 - 94 (-24.25)

       I = 3125.5 N s

d)     F = I / t

       F = 3125.5 / 6 10⁻³

       F = 5.21 10⁵ N

7 0
3 years ago
A 1500 kg truck traveling at 80 km/h collides with another car of mass 1000 kg traveling at 30 km/h in the same direction. The t
Likurg_2 [28]

Answer:

Their speed immediately after the collision is 60 km/h

Explanation:

The magnitude that characterizes the state of motion of a body is called the quantity of motion. The momentum of a particle of mass m moving with velocity v is defined as the product of mass and velocity:

p=m*v

Newton's second law states that to accelerate an object you must apply a force to it. In other words, to change the moment of an object, an impulse must be applied to it, an impulse that is produced by a force. In both cases there is an external agent that exerts the force or the impulse, the internal forces are not considered. When the force  net is zero, so the net momentum is zero, and therefore there is no change in total momentum. Then it can be stated that if a net force is not exerted on a system, the total moment of the system cannot change.

In summary, the principle of conservation of linear momentum, also known as the principle of conservation of momentum, states that if the resultant of the forces acting on a body or system is zero, its momentum remains constant in time.

Then before collision, the momentum of truck is  1,500 kg*80 km/h = 120,000 kg.km/h  and the momentum of car is  1,000 kg* 30 km/h = 30,000 kg.km/h

So, the total momentum before collision is  120,000 kg*km/h+ 30,000 kg*km/h = 150,000 kg.km/h

The two cars stick together after the collision. This means that the speed V of both is the same. Therefore, the momentum after collision is  

V*(1,500 kg + 1,000 kg)  = V*2,500 kg

Applying the law of conservation of momentum, that it states that the total momentum of two objects before collision is equal to the total momentum of the two objects after collision., you get:

150,000 kg.km/h= V*2,500 kg

Solving:

V=\frac{ 150,000 kg.km/h}{2,500 kg}

V= 60 km/h

<u><em>Their speed immediately after the collision is 60 km/h</em></u>

7 0
3 years ago
(for astronomy class)
Dafna11 [192]

Answer:

d

Explanation:

astroids are not the same size so if a big astroid gets to close to a small one they will make contact or the small astroid will orbit the bigger one

7 0
2 years ago
Read 2 more answers
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