Answer:
bromine
Explanation:
Any element in the halogen group will have seven valence electrons. These elements include fluorine, chlorine, bromine, iodine, and astatine
Answer : The correct option is (d) 2.73 m
Explanation :
By the 2nd equation of motion,

where,
s = distance or height = ?
u = initial velocity = 3.0 m/s
t = time = 0.5 s
a = acceleration due to gravity = 
Now put all the given values in the above equation, we get:


Therefore, the correct option is (d) 2.73 m
Answer:

Explanation:
If the collision is elastic and exactly head-on, then we can use the law of momentum conservation for the motion of the 2 balls
Before the collision

After the collision

So using the law of momentum conservation


We can solve for the speed of ball 1 post collision in terms of others:

Their kinetic energy is also conserved before and after collision


From here we can plug in 






Answer:
2.210N
Explanation:
Workdone = Force x distance
Distance = 38m , Workdone = 84J
Hence 84J = Force x 38m
Force = 84J / 38m
Force = 2.210N =2.2N
Answer:
work done lifting the bucket (sand and rope) to the top of the building,
W=67.46 Nm
Explanation:
in this question we have given
mass of bucket=20kg
mass of rope=
height of building= 15 meter
We have to find the work done lifting the bucket (sand and rope) to the building =work done in lifting the rope + work done in lifting the sand
work done in lifting the rope is given as,
=
..............(1)
=
=22.5 Nm
work done in lifting the sand is given as,
.................(2)
Here,
F=mx+c
here,
c=20-18
c=2
m=
m=.133
Therefore,

Put value of F in equation 2


Therefore,
work done lifting the bucket (sand and rope) to the top of the building,
W=22.5 Nm+44.96 Nm
W=67.46 Nm