Answer:
Explanation:
mass of car, m = 1000 kg
initial velocity, u = 20 m/s
final velocity, v = 0 m/s
distance, s = 120 m
Let a be the acceleration of motion
use third equation of motion
v² = u² + 2 as
0 = 20 x 20 + 2 x a x 120
a = - 1.67 m/s²
Let F be the force
Force, F mass x acceleration
F = - 1000 x 1.67
F = - 1666.67 N
The direction of force is towards south and the magnitude of force is 1666.67 N.
We know the equation of motion v = u+ at, where v is the final velocity, u is the initial velocity, a is the acceleration and t is the time taken.
In this case Final velocity = -3.1 m/s, negative sign indicates it is pointing downward.
acceleration = - 3.7m/
. Negative means acceleration is towards center of planet Mars.
Time taken = 3 seconds
So jumping velocity of Julia = 8 m/s
Answer:
C. Both reach the bottom at the same time.
Explanation:
For a rolling object down an inclined plane , the acceleration is given below
a = g sinθ / (1 + k² / r² )
θ is angle of inclination , k is radius of gyration , r is radius of the cylinder
For cylindrical object
k² / r² = 1/2
acceleration = g sinθ /( 1 + 1/2 )
= 2 g sinθ / 3
Since it does not depend upon either mass or radius , acceleration of both the cylinder will be equal . Hence they will reach the bottom simultaneously.
Answer:
Explanation:
The pail is rotated at a constant rate in vertical circular path so it has the minimum speed at all points along its circular path . That means at top position the velocity is almost zero. In that case the centripetal force at top position will be provided by its weight or
mg = mv² / r ( r is radius of vertical circular path )
v = √ rg
At the bottom position its velocity will be increased due to loss of potential energy
so 1/2 m V² = 1/2 m v² + mg x 2r
V =√ 5 gr
If R be the reaction force at the bottom by bottom of pail
R - mg = mV² / r
R = mg +mV² / r
= mg + m x 5gr / r
R = 6mg
This is the magnitude of the force exerted by the water on the bottom of the pail .
