The speed of the tennis ball is 8 km/h when Alana throws the ball behind at the speed of 11 km/h.
<h3>What is the
frame of
reference?</h3>
It is a point from where the motion is observed. The speed changes with the frame of reference.
For the person standstill on the sidewalk, If Alana throw the ball in the front direction, The speed will be,
19+11 = 30 km/h
It Alana just leave the ball, the speed,
19 +0 = 19 km/h
If Alana throws the ball behind her at the speed of 19 km/h. The speed of the ball for a sidewalk observer,
19 +(-19 ) = 0 km/h
Thus, when Aana throw the ball behind the velocity will be negative,
So,
19 + (-11 ) = 8 km/h
Therefore, the speed of the tennis ball is 8 km/h when Alana throws the ball behind at the speed of 11 km/h.
Learn more about Frame of reference:
brainly.com/question/9820962
Answer:
a is 4.6 x 10-2m
b is 1x8204m
Explanation:
The fire net is actually going past zero into a negative vertical displacement. Essentially because again, we're saying that why initial equals thirty eight meters. The person is falling down to zero meters. Zero meters is where the fire that is. And then after the person stretches the fire. Yet it has a certain vertical displacement. But this particles placement is negative. So here we're going to choose the negative value. so trying to see how much of the fire net would stretch if the person was lying on tough it and if the person jumped from a height of thirty eight meters. So for here Mass is going to be equal to sixty two kilograms and why initial for party is going to be twenty meters and then why final is going to be negative one point four meters And so in order to find in order to find this is an instance, essentially, this is an instance perspective in the sense that we need this data in order to figure out this during constant so we can see that energy initial equals energy final and then we consider it mg y initial equals mg.
Answer:
Explanation:
Magnetic field B = 5 x 10⁻³ T
Speed of electron
= ( 5.5 /100) x 3 x 10⁸
= 165 x 10⁵ m /s
Magnetic force on electron
F = Bqv
B is magnetic field , q is charge on electron and v is its velocity
= 5 x 10⁻³ x1.6 x 10⁻¹⁹ x 165 x 10⁵
1320 x 10⁻¹⁷ N
13.2 X 10⁻¹⁵ N
= 13.2 f N
b )
Acceleration = force / mass of electron
= 1320 x 10⁻¹⁷ / 9.1 x 10⁻³¹
= 14.5 x 10¹⁵ m/s²
= 14.5 Pm/s²
c ) The direction of the moving electron will change but its speed will remain constant.
This is so because the magnetic force will be acting perpendicular to the velocity of electron all the time in course of its motion.
A neutral metal sphere is touched by a negatively charged metal rod. ... If a negative object is used to charge a neutral object, then both objects become charged negatively. In order for the neutral sphere to become negative, it must gain electrons from the negatively charged rod.
