Answer:
v = 2.18m/s
Explanation:
In order to calculate the speed of Betty and her dog you take into account the law of momentum conservation. The total momentum before Betty catches her dog must be equal to the total momentum after.
Then you have:
(1)
M: mass Betty = 40kg
m: mass of the dog = 15kg
v1o: initial speed of Betty = 3.0m/s
v2o: initial speed of the dog = 0 m/s
v: speed of both Betty and her dog = ?
You solve the equation (1) for v:
The speed fo both Betty and her dog is 2.18m/s
it would be C laminated soda lime glass
Answer:
B)
Explanation:
The value the scale shows is the reaction force to the normal force (they are equal by Newton's 3rd Law) that the scale exerts on Eric.
The forces on Eric are his weight (downward) and this normal force (upward), so we can write the net force over him as (also using Newton's 2nd Law):
which means
and for our values this is:
Explanation:
The new volume of water = 25 ml
The old volume of water = 15 ml
The difference = 25 - 15 but what are the units?
Since the question asks for force, the units must start out as 10 mL
In water 1 mL has a mass of 1 gram, so the answer is 10 grams.
Grams are units of mass, not weight. You should convert this into newtons.
10 grams = 1/1000 = 0.01 kg
1 kg has a weight of 9.81 Newtons
0.01 kg has a weight 0.081 Newtons
If you have never seen a Newton before, then the answer is 10 grams
-- During the time the ball is flying from the high roof to the low roof,
it's going to fall (100-25) = 75 meters.
How long does it take an object dropped from rest to fall 75 meters ?
Distance = (1/2) · (gravity) · (time)²
75 m = (4.9 m/s²) · (time)²
Time² = (75 m) / (4.9 m/s²)
Time² = 15.31 sec²
Time = √(15.31 sec²) = 3.91 seconds
So the ball has to cover the horizontal distance of 20 meters
in 3.91 seconds.
Distance = (speed) · (time)
20 m = (speed) · (3.91 sec)
Speed = (20 m) / (3.91 sec)
Speed = 5.11 m/s
