Answer:
5 m/s
Explanation:
The formula of speed is : distance/time taken.
The skateboarder covered a distance of 20 meters in 4 seconds. So,
Distance = 20 meters
Time Taken = 4 seconds
Speed = 20/4 = 5 m/s
Answer:
66.98 db
Explanation:
We know that
L_T= Total signal level in db
n= number of sources
L_S= signal level from signal source.
= 66.98 db
Answer:
B
Explanation:
Solution:-
- Take a coordinate system as follows:
x: Directed along the ground
y: Directed vertical to ground
- We will assume that the initial vertical and horizontal non-zeroes velocities are given as follows:
- After a ball is thrown it continues a path of parabolic projectile. The motion of the ball can be analyzed in each coordinate system. We will assume that effects of air-resistance are negligible.
- Therefore, only gravity acts on the ball in the vertical direction. We can use kinematic equation of motions to determine the velocity of ball in either ( x-y ) direction at any instant of time ( t ).
- Use first kinematic equation of motion in both x and y directions.
- The accelerations ( ax and ay ) in the direction of each axis are to be determined. We know that the gravity acceleration ( g ) acts in vertical direction or along y-axis ( ay ) and always directed downwards while velocity is directed up. Since, we neglected the effects of air-resistance there is no acceleration in the x-direction ( ax = 0 ) .
- We see that the horizontal velocity of the ball ( vxf ) at any point in time remains equal to the initial horizontal velocity; hence, it is constant throughout the journey.
- However, the velocity of the ball in vertical direction( vyf ) is changing for every unit of time ( t ) under the influence of gravitational acceleration. Hence, it is not constant throughout the journey
Answer:
Explanation:
When force applied to the end of the rod in perpendicular direction then net torque on the rod is given as
Now another force is applied at mid point of the rod at an angle of 30 degree with the rod
so new value of torque is given as
so we have