Answer:
400 N
Explanation:
By the law of friction,
is the maximum frictional force, 
is the coefficient of friction and 
is the reaction on the refrigerator. On a horizontal surface, the reaction is equal to the weight of the refrigerator.
While not moving, the fricition on the refrigerator is static friction. So, 
This is the maximum frictional force and is more than the applied horizontal force of 400 N. Frictional force cannot be more than the applied force, else it would actually pull the refrigerator backwards (a strange thing, if it were to happen). It is equal to the extent of the applied force because the applied force is not enough to overcome the maximum.
Hence the frictional force is 400 N.
PS: Note that we do not use the coefficient of kinetic friction because applied force could not overcome the static friction.
Answer:
Associations Clusters
Explanation:
There is three basic type of clusters, globular clusters, open clusters, associations clusters. Associations cluster consist of younger stars that is younger than globular and open clusters stars.
1 m/s
Explanation:
To solve this question we use the following formula:
momentum = mass × velocity
momentum of the first car = 1000 kg × 2.5 m/s
momentum of the second car = 2500 kg × X m/s
To bring the cars at rest the momentum of the first car have to be equal to the momentul of the second car.
momentum of the first car = momentum of the second car
1000 kg × 25 m/s = 2500 kg × X m/s
X (velocity of the second car) = (1000 × 25) / 2500 = 1 m/s
Learn more about:
momentum
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Explanation:
Following are two interactions that are generally involved when we use a TV remote control to change the channel :
1. Figure touches remote buttons, and its a short range interaction.
2. Now remote sends signal to Television, this is a long range interaction.
<span>7.7 m/s
First, determine the acceleration you subject the sled to. You have a mass of 15 kg being subjected to a force of 180 N, so
180 N / 15 kg = 180 (kg m)/s^2 / 15 kg = 12 m/s^2
Now determine how long you pushed it. For constant acceleration the equation is
d = 0.5 A T^2
Substitute the known values getting,
2.5 m = 0.5 12 m/s^2 T^2
2.5 m = 6 m/s^2 T^2
Solve for T
2.5 m = 6 m/s^2 T^2
0.41667 s^2 = T^2
0.645497224 s = T
Now to get the velocity, multiply the time by the acceleration, giving
0.645497224 s * 12 m/s^2 = 7.745966692 m/s
After rounding to 2 significant figures, you get 7.7 m/s</span>
