Answer:
4.15 m/s
Explanation:
Its given that acceleration is 0.1 m/s² with a direction opposite to the velocity. Since, the direction of acceleration is opposite to the velocity, this gives us a hint that the velocity is decreasing and so acceleration would be negative.
i.e.
acceleration = a = - 0.1 m/s²
Distance covered = S = 6m
Velocity after covering 6 meters = Final velocity = 
= 4 m/s
We need to find the initial speed, which will be the same as the magnitude of initial velocity.
Initial velocity = 
= ?
3rd equation of motion relates the acceleration, distance, final velocity and initial velocity as:
Using the known values in the formula, we get:
Thus, the initial speed of the ball was 4.15 m/s
Answer:
Explanation:
charge, q = 10 C
time, t = 2 micro second
Current, i = q / t
i = 10 / (2 x 10^-6) = 5 x 10^6 A
(a)
distance, d = 1 m
the formula for the magnetic field is given by
B = 1 Tesla
Now the distance is d' = 1 km = 1000 m
B' = 0.001 Tesla
(b) The magnetic field of earth is Bo = 3 x 10^-5 tesla
B / Bo = 3.3 x 10^4
B'/Bo = 33.3
Let the mass of the person be m. Total momentum is conserved (because the exterior forces on the system are balanced), especially the component in the vertical direction.
Given that,
Mass of gallon is M
Let man mass be m
Velocity of man is v
Let velocity if ballot be Vb
When the person begin to move we have
Conservation of momentum
mv + MVb=0
MVb=-mv
Vb= -(m/M) v
Given that the mass of man is less than mass of balloon. i.e. m<M
So, if m<M, then, m/M <1
Therefore, .
Vb= -(m/M) v
Vb< -v
This implies that the velocity of balloon is less than the velocity of man and if is also moving in opposite direction
So the man is moving upward, then the balloon is moving downward and it's velocity is less than the velocity of man,
The answer is C
Down with a speed less than v
The correct answer is: Option (A) 75 J
Explanation:
First, be careful with the units here. As you can see it is mentioned that there is a 50N box. It means that the weight (<em>mg</em>) of the box is given as the unit is <em>Newton</em>, not its mass (which is in kg).
As,
Potential-energy = mass * acceleration-due-to-gravity * height
PE = m*g*h --- (A)
In equation (A), mg is actually the weight of the box, which is given.
mg = 50N
h = height = 1.5m
Plug the values in equation (A):
PE = 50 * 1.5 = <em>75 J (Option A)</em>
