Answer:
v = 4.18 m/s
Explanation:
given,
frequency of the alarm = 872.10 Hz
after passing car frequency she hear = 851.10 Hz
Speed of sound = 343 m/s
speed of the jogger = ?
speed of the
v_o = 872.1 - 10.5
The speed of jogger
v = 4.18 m/s
A bullet with kinetic energy of 400J strikes a wooden block where a 8.00x10N resistive force stops the bullet what is the penetr
1 answer:
The "penetration of the bullet" is 5 m
<u>Explanation</u>:
A "bullet" with "kinetic energy" of = 400J
A resistive force stops the bullet = 8.00 x 10 N
Work = change in energy
Work = ∆ Kinetic Energy (equation 1)
Work = (equation 2)
From equations 1 and 2 we have,
= ∆ Kinetic Energy
Where ,
Kinetic Energy = 400 J
F = 8.00 x 10 N
(8.00 x 10 N) d = 400 J
(80 N) d = 400 J
d = 5 m
The penetration of the bullet is 5 m
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Answer:
The maximum height reached is 4.63 m.
Explanation:
Given:
Initial speed of the man (u) = 31.0 m/s
Speed at the top of trajectory () = 29.5 m/s
Acceleration due to gravity (g) = 9.8 m/s²
When the man reaches the top of the trajectory, the vertical component of velocity becomes zero and hence only horizontal component of velocity acts on him.
Also, since there is no net force acting in the horizontal direction, the acceleration is zero in the horizontal direction from Newton's second law. Thus, the horizontal component of velocity always remains the same.
So, speed at the top of trajectory is nothing but the horizontal component of initial velocity.
Now, initial velocity can be rewritten in terms of its components as:
Where, are the initial horizontal and vertical velocities of the man.
Now, plug in the given values and simplify. This gives,
Now, we know that, for a projectile motion, the maximum height is given as:
Plug in the value from equation (1) and 9.8 for 'g' to solve for 'H'. This gives,
Therefore, the maximum height reached is 4.63 m.