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Elodia [21]
3 years ago
8

A 30.0 kg dolphin decelerates from 12.0 to 7.00 m/s in 2.60 s to join another dolphin in play. What average force (in N) was exe

rted to slow him if he was moving horizontally? (The gravitational force is balanced by the buoyant force of the water. Assume the positive direction is in the direction of motion. Indicate the direction with the sign of your answer.)
Physics
1 answer:
Crazy boy [7]3 years ago
7 0

Answer:

Force is 57.69 N to the opposite direction of motion of dolphin.

Explanation:

We have force is the product of mass and acceleration.

That is    

                 Force = Mass x Acceleration

                         F = ma

Mass of dolphin, m = 30 kg

We have equation of motion, v = u + at

Final velocity, v = 7 m/s

Initial velocity, u = 12 m/s

Time, t = 2.60 s

Substituting

                   7 = 12 + a x 2.6

                    a = -1.92 m/s²

Force,   F = 30 x -1.92 = -57.69 N

So the force is 57.69 N to the opposite direction of motion of dolphin.

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A force of 10N acts on a car for 3 seconds. The impulse imparted on the car is
ss7ja [257]

Answer:

30N*s

Explanation:

Given the following data;

Force = 10N

Time = 3 seconds

To find the impulse;

Impulse = force * time

Substituting into the equation, we have;

Impulse = 10 * 3

Impulse = 30Ns

7 0
3 years ago
I need help with life a child is adopted and I’m a duck where is my left shoe
Pavel [41]

just swim In water and find your shoe

8 0
3 years ago
Read 2 more answers
An electroscope is a simple device consisting of a metal ball that is attached by a conductor to two thin leaves of metal foil p
baherus [9]

Answer:

the electroscope separate  by the presence of charge carriers

Explanation:

Metal bodies are characterized by having free (mobile) electrons. In the electroscope the plates are in balance; when the external metal ball is touched, a charge is introduced into the device, when the body that touched the ball is separated, an excess charge remains. This charge, being a metal, is distributed over the entire surface, giving a uniform density and an electric force of repulsion is created between the two charged sheets, which tends to separate the sheets. This force is counteracted by the tension component as the sheets are separated at a given angle, the separation reaches the point where

                  Fe - Tx = 0

                  Fe = Tx

In summary, the electroscope separate its leaves by the presence of charge carriers

3 0
3 years ago
A person is trying to lift a crate that has a mass of 30 kg. The normal force of the floor is currently supplying 150N of force.
alexdok [17]

Here when an object is placed on the level floor then in that case there are two forces on the object

1). Weight of object downwards (mg)

2). Normal force due to floor which will counterbalance the weight (N)

so when no force is applied on the box at that time normal force is counter balanced by weight.

Now here it is given that A person tried to lift the box upwards

So now there are two forces on the box

1). Applied force of person

2). Normal force due to ground

So now these two forces will counter balance the weight of the crate

So we can write an equation for force balance like

F_g = F_n + F_a

given that

F_g = mg

here

m = 30 kg and

g = acceleration due to gravity = 10 m/s^2

F_n = 150 N

now from above equation

30*10 = 150 + F_a

F_a = 300 - 150 = 150 N

So force applied by the person must be 150 N

7 0
4 years ago
Over a time interval of 1.99 years, the velocity of a planet orbiting a distant star reverses direction, changing from +20.7 km/
madam [21]

Answer:

(a) - 42700 m/s

(b) - 6.8 x 10^-4 m/s^2

Explanation:

initial velocity of star, u = 20.7 km/s

Final velocity of star, v = - 22 km/s

time, t = 1.99 years

Convert velocities into m/s and time into second

So, u = 20700 m / s

v = - 22000 m/s

t = 1.99 x 365.25 x 24 x 3600 = 62799624 second

(a) Change in planet's velocity = final velocity - initial velocity

  = - 22000 - 20700 = - 42700 m/s

(b) Accelerate is defined as the rate of change of velocity.

Acceleration = change in velocity / time

                     = ( - 42700 ) / (62799624) = - 6.8 x 10^-4 m/s^2

8 0
4 years ago
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