One runner in a relay race has a 1.50 s lead and is running at a constant speed of 3.25 m/s. The runner has 30.0 m to run before
2 answers:
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Answer:
-22,150 N
Explanation:
When the youngster jumps off the platform, during the fall her initial potential energy is converted into kinetic energy, according to the law of conservation of energy. Therefore, we can write:
where the term on the left is the potential energy while the term on the right is the kinetic energy, and where
m = 50.0 kg is the mass of the youngster
is the acceleration due to gravity
h = 1.00 m is the heigth of the platform
u is the speed of the youngster as she reaches the floor
Solving for u,
Then, when the youngster hits the floor, the force exerted on her during the deceleration is given by:
where is her change in momentum, and where
m is the mass
v = 0 is the final velocity (she comes to a stop)
u = 4.43 m/s is the initial velocity
is the duration of the collision
Substituting,
And the negative sign means the direction of the force is opposite to the motion (so, upward).
Answer:
d. Two soccer balls that are touching each other
Explanation:
Let be the mass of a tennis ball,
is the mass of a soccer ball.
As the mass of a soccer ball is more than the mass of a tennis ball, so
Let be the distance between the centers of both the balls near each other and
be the distance between the centers of both the balls touching each other.
So,
The gravitational force, F, between the two objects having masses M and m and separated by distance d is
Where G is the universal gravitational constant.
As, the gravitational force is directly proportional to the product of both the masses and inversely proportional to the square of the distance between them, so selecting the larger mass (, soccer ball) separated by a lesser distance (
, touching) to get more gravitational force.
Therefore, there will be a larger gravitational force between them when two soccer balls touching each other.
Hence, option (d) is correct.