Answer:
1.6s
Explanation:
Given that A 1.20 kg solid ball of radius 40 cm rolls down a 5.20 m long incline of 25 degrees. Ignoring any loss due to friction,
To know how fast the ball will roll when it reaches the bottom of the incline, we need to calculate the acceleration at which it is rolling.
Since the frictional force is negligible, at the top of the incline plane, the potential energy = mgh
Where h = 5.2sin25
h = 2.2 m
P.E = 1.2 × 9.8 × 2.2
P.E = 25.84 j
At the bottom, K.E = P.E
1/2mv^2 = 25.84
Substitutes mass into the formula
1.2 × V^2 = 51.69
V^2 = 51.69/1.2
V^2 = 43.07
V = 6.56 m/s
Using the third equation of motion
V^2 = U^2 + 2as
Since the object started from rest,
U = 0
6.56^2 = 2 × a × 5.2
43.07 = 10.4a
a = 43.07/10.4
a = 4.14 m/s^2
Using the first equation of motion,
V = U + at
Where U = 0
6.56 = 4.14t
t = 6.56/4.14
t = 1.58s
Therefore, the time the ball rolls when it reaches the bottom of the incline is approximately 1.6s
Larger mass creates a stronger pull
Answer:
number 3 is the 3rd one and number 2 is the 4 one and number 1 is the 2nd one
Answer:

Explanation:
Given data:
Momentum of moving model train, 
Mass of the stationary model train, 
Initial speed of the stationary model train, 
Assume there is no external force is acting on the given train system.
In this case, the total linear momentum of the trains would be conserved.
Let the final linear momentum of the trains be 
Thus,





It really depends on the altitude of the barometer.
-- If the picture was taken in Denver, Colorado, where the long-term
average atmospheric pressure is around 24.5", then this barometer
is showing slightly higher than normal, and good weather can be
predicted.
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where standard "sea level" pressure is 29.92", then this barometer
is reading alarmingly low ! There's either a hurricane in progress
right now, or one can be predicted to arrive very soon and you'd best
pick up your barometer and head inland as fast as you can.