When a 2.50 kg object is hung vertically on a certain light spring described by hookes law the spring stretches 2.76 cm.
1 answer:
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I assume L=120 yards as the length of the football field.
1) The average speed is given by the total distance covered by the player divided by the time taken.
The total distance covered to go from one goal line to the other and then back to the 40-yards line is
And the time taken is t=22.4 s, so the average speed of the player is
2) The find the average velocity, we should also consider the direction (and the sign) of the velocity.
In the the first part of the motion, the player goes from one goal line to the other one, so he covers 120 y. However, in the second part of the motion he goes back by 80 y. Therefore, the net displacement of the player is
and so, the average velocity is
1) The average speed is given by the total distance covered by the player divided by the time taken.
The total distance covered to go from one goal line to the other and then back to the 40-yards line is
And the time taken is t=22.4 s, so the average speed of the player is
2) The find the average velocity, we should also consider the direction (and the sign) of the velocity.
In the the first part of the motion, the player goes from one goal line to the other one, so he covers 120 y. However, in the second part of the motion he goes back by 80 y. Therefore, the net displacement of the player is
and so, the average velocity is
Answer:
D. 48.985 N
Explanation:
Newton's second law states that:
which means that the net force acting on an object is equal to the product between the object's mass and its acceleration.
The equation of the forces for the briefcase in the elevator therefore is given by:
where
N is the normal reaction exerted on the briefcase
(mg) is the weight of the briefcase, with
m = 4.5 kg being its mass
g = 9.8 m/s^2 is the acceleration of gravity
a = 1.10 m/s^2 is the acceleration
Here we chose upward as positive direction.
Solving for N, we find the normal force:
So the closest answer is
D. 48.985 N