Answer:
Explanation:
The acceleration of an object is the rate of change of velocity of the object; it is given by:
where
u is the initial velocity of the body
v is its final velocity
t is the time elapsed
In this problem, we have:
u = 5.0 m/s is the initial velocity of the skater
v = 10.0 m/s is the final velocity
t = 5 s is the time elapsed
Therefore, the acceleration of the skater is:
You can do this two ways:
1). Whatever kinetic energy the rolling ball has is the amount
of energy you have to absorb in order to stop it.
2). Whatever momentum the rolling ball has is the amount of
momentum you have to provide in the other direction to cancel it.
Since you asked about force and time, we sense 'impulse' in the
air, and we know that impulse is exactly a change in momentum.
So let's use #2 and talk about momentum and impulse.
Impulse = (force) x (time)
Momentum of a moving object is (mass) x (speed) .
-- Momentum of the first ball: (8 kg) x (0.2 m/s) = 1.6 kg-m/s
Impulse required to stop it = 1.6 kg-m/s
(force) x (10 sec) = 1.6
Force required = 1.6 / 10 = 0.16 Newton .
-- Momentum of the second ball: (4 kg) x (1 m/s) = 4 kg-m/s
Impulse required to stop it = 4 kg-m/s
(force) x (10 sec) = 4
Force required = 4 / 10 = 0.4 Newton .
You need more force o stop the second ball. Although its mass
is only 1/2 the mass of the 8kg ball, it's moving 5 times as fast,
and has 2.5 times the momentum of the bigger ball.
So you need 2.5 times as much impulse to stop it.
If you're going to push on each ball for the same length of time,
then you need to push 2.5 times as hard on the smaller ball in
order to stop it.
D, it provides greater accuracy for measuring stars far from the earth.
Answer: What is the acceleration of an object that moves at constant velocity? Acceleration is Zero
What is the net force on the object in this case? The ner force is also Zero
Explanation: If the velocity is constant means that the acceleration is zero, from Newton second law is clear that net force is also zero
Fnet= m* a as v is constant a=0 this Fnet is zero.
Answer:
12 grams of Iodine-13 was present 16 days ago
Explanation:
Given:
Amount of Iodine-131 sample present now = 3g
To Find:
Amount of Iodine-131 sample present before 16 days = ?
Solution:
W know that the half life of Iodine-131 is 8days
Let the amount of sample before 16 days be X
Then
The X amount Iodine-131 sample will decay ito ist half after 8 days
after 8 days
=> 
=> 
after next 8 days , i.e., 16 days
=> 
=> 
Now we know that after 16 days we have 3 grams of Iodine-131 sample
So,
= 3
X = 12
