Answer:
The answer is the option a.
Explanation:
We know that magnetic force (Fm) is defined as
Fm = q (v x B)
Where q is a the value of the charge, v is the velocity of the charge and B is the value of the magnetic field.
"v x B" is defined as the cross product between the vectors velocity and magnetic field, and if the angle between them is thetha < 180°, then, the cross product is
v x B = vBsin (thetha)
So,
Fm = qvBsin (thetha)
And, in case in which v and B are parallel vectors, thetha is zero, and,
sin (thetha)=sin (0) = 0
So, Fm=0
The actual answer is 7/100
Answer:
the magnitude of the velocity of the block just after impact is 2.598 m/s and the original speed of the bullect is 324.76m/s.
Explanation:
a) Kinetic energy of block = potential energy in spring
½ mv² = ½ kx²
Here m stands for combined mass (block + bullet),
which is just 1 kg. Spring constant k is unknown, but you can find it from given data:
k = 0.75 N / 0.25 cm
= 3 N/cm, or 300 N/m.
From the energy equation above, solve for v,
v = v √(k/m)
= 0.15 √(300/1)
= 2.598 m/s.
b) Momentum before impact = momentum after impact.
Since m = 1 kg,
v = 2.598 m/s,
p = 2.598 kg m/s.
This is the same momentum carried by bullet as it strikes the block. Therefore, if u is bullet speed,
u = 2.598 kg m/s / 8 × 10⁻³ kg
= 324.76 m/s.
Hence, the magnitude of the velocity of the block just after impact is 2.598 m/s and the original speed of the bullect is 324.76m/s.
<h2>
Option 3, 216 m is the correct answer.</h2>
Explanation:
We have initial velocity, u = 15 m/s
Time, t = 12 seconds
Final velocity, v = 21 m/s
We have equation of motion v = u + at
Substituting
21 = 15 + a x 12
a = 0.5 m/s²
Now we have equation of motion v² = u² + 2as
21² = 15² + 2 x 0.5 x s
s = 216 m
Displacement = 216 m
Option 3, 216 m is the correct answer.
Explanation:
Speed of Bob, v = 0.967 c
At the exact instant he passes Alice, she fires a very short laser pulse in the same direction Bob is moving.
(a) We need to find the distance measured by Alice between Bob and the laser pulse. It is given by :




(b) Distance measured by Bob between himself and the laser pulse is given by :



Hence, this is the required solution.