Answer:
<h2>a) t = 4</h2>
Explanation:
In projectile the time taken by an object to reach its maximum height is the maximum time (tmax).
tmax = Usin
/g
U = velocity of the ball
= angle of projection = 90° (vertical velocity)
g = acceleration due to gravity = 9.8m/s²
tmax = Usin90°/9.8
tmax = U/9.8
T the maximum height U = Uy = 39.2 m/s²
tmax = 39.2/9.8
tmax = 4secs
To calculate the time at which the ball will have an horizontal velocity, we will use the same formula but
will be 0° in this case
If Ux = Ucos
8 = Ucos0
U = 8m/s
Since t = Usin
/g
t = 8sin0/9.8
t = 0sec
Answer:
c
Explanation:
the charge wants to ultimately balance out so either you or the slide gave the other electrons to balance the charges
Displace/time=velo
8000/12 = 666.666666667 speed
Answer:
kinetic friction may be greater than 400 N or smaller than 400 N
Explanation:
As we know that maximum value of static friction on the rough surface is known as limiting friction and the formula of this limiting friction is known as

now when object is sliding on the rough surface then the friction force on that surface is known as kinetic friction and the formula of kinetic friction is known as

now we know that

so here value of limiting static friction force is always more than kinetic friction
also we know that
initially when body is at rest then static friction value will lie from 0 N to maximum limiting friction
and hence kinetic friction may be greater than static friction or if the static friction is maximum limiting friction then kinetic friction is smaller than static friction
so kinetic friction may be greater than 400 N or smaller than 400 N