Explanation:
(a) Net force acting on the block is as follows.

or, ma = -mg Sin (\theta)[/tex]
a = 
= 
= -3.35 
According to the kinematic equation of motion,

Distance traveled by the block before stopping is as follows.
s = 
= 
= 21.5 m
According to the kinematic equation of motion,
v =
0 = 
= 7.16 sec
Therefore, before coming to rest the surface of the plane will slide the box till 7.16 sec.
(b) When the block is moving down the inline then net force acting on the block is as follows.

ma = 
a = 
= 
= 3.35 
Kinematics equation of the motion is as follows.
s = 
21.5 m = 
= 
= 3.58 sec
Hence, total time taken by the block to return to its starting position is as follows.
t = 
= 7.16 sec + 3.58 sec
= 10.7 sec
Thus, we can conclude that 10.7 sec time it take to return to its starting position.
Answer:
0.0195 m
Explanation:
= density of hockey puck = 9.45 gcm⁻³ = 9450 kgm³
= diameter of hockey puck = 13 cm = 0.13 m
= height of hockey puck = 2.8 cm = 0.028 m
= density of mercury = 13.6 gcm⁻³ = 13600 kgm³
= depth of puck below surface of mercury
According to Archimedes principle, the weight of puck is balanced by the weight of mercury displaced by puck
Weight of mercury displaced = Weight of puck

We know that the Pythagorean theorem applies only to right triangles, therefore the original vectors must be parallel to the legs of a right triangle.
In other words, they must be orthogonal (i.e. perpendicular to each other) in order that the Pythagorean theorem applies.
Answer:
4. To the east
Explanation:
Friction forces always act in the opposite direction that an object tends to move in. In this case, when the truck accelerates to the east, the crate tends to move to the west due to inertia (the tendency for an object to remain at rest or at constant speed). In order to stop the crate from moving, there needs to be a friction force to the east.
Answer:
Explanation:
mass number is now 4 times less than the original value so alpha decay occur during alpha decay the mass number is decreased 4 times and atomic number decreased 2 times than the original value