Question: How fast was the arrow moving before it joined the block?
Answer:
The arrow was moving at 15.9 m/s.
Explanation:
The law of conservation of energy says that the kinetic energy of the arrow must be converted into the potential energy of the block and arrow after it they join:
where 
is the mass of the arrow, 
is the mass of the block, 
of the change in height of the block after the collision, and 
is the velocity of the arrow before it hit the block.
Solving for the velocity , we get:
and we put in the numerical values
,
and simplify to get:
The arrow was moving at 15.9 m/s
Answer:
The work done against gravity is 78.4 J
Explanation:
The work is calculated by multiplying the force by the distance that the
object moves
W = F × d, where W is the work , F is the force and d is the distance
The SI unit of work is the joule (J)
We need to find the work done against gravity when lowering a
16 kg box 0.50 m
→ F = mg
→ m = 16 kg, and g = 9.8 m/s²
Substitute these value in the rule
→ F = 16 × 9.8 = 156.8 N
→ W = F × d
→ F = 156.8 N and d = 0.50
Substitute these values in the rule
→ W = 78.4 J
<em>The work done against gravity is 78.4 J</em>
Answer:
I believe its B and C
Explanation:
<u><em>If I'm wrong please tell me so I can correct my answer.</em></u>
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Answer:
19.2*10^6 s
Explanation:
The equation for time dilation is:
Then, if it is observed to have a life of 6*10^6 s, and it travels at 0.95 c:
It has a lifetime of 19.2*10^6 s when observed from a frame of reference in which the particle is at rest.
The velocities and the speed build a triangle, where the 1.7 m/s are the hypotenuse and the x-velocity and y-velocity are the other sides.
<span>So the x-velocity is: speed*cos(angle) </span>
<span>now plug in </span>
<span>x=1.7 m/s * cos(18.5)=1.597 m/s </span>
