Answer:
1) t=1.743 sec
2)Vo=61.388  m/sec
3)the x component of its velocity just be- fore it strikes the ground is the same as the  initial velocity of the ball that is=61.388  m/sec
4)Vf=17.08 m/s
Explanation:
1)From second equation of motion we get
h=Vit+(1/2)gt^2
here in case(a): Vi=0 m/s,h=14.9m,,put these values in above equation to find the time the ball is in motion
14.9=(0)*t+(1/2)(9.8)t^2
t^2=14.9/4.9
t^2=3.040 sec
t=1.743 sec
2) s=Vo*t
Putting values we get
107=Vo*1.743
Vo=61.388  m/sec
3)the x component of its velocity just be- fore it strikes the ground is the same as the  initial velocity of the ball that is=61.388  m/sec
4)From third equation of motion we know that
Vf^2-Vi^2=2gh
here Vi=0 m/s,h=14.9 m
Vf^2=Vi^2+2gh=0+2(9.8)(14.9)
Vf^2=292.04
Vf=17.08 m/s
 
        
             
        
        
        
Answer:
-1.43 m/s relative to the shore
Explanation:
Total momentum must be conserved before and after the run. Since they were both stationary before, their total speed, and momentum, is 0, so is the total momentum after the run off:
 
where  are the mass of the swimmer and raft, respectively.
 are the mass of the swimmer and raft, respectively.  are the velocities of the swimmer and the raft after the run, respectively. We can solve for
 are the velocities of the swimmer and the raft after the run, respectively. We can solve for  
 
 
So the recoil velocity that the raft would have is -1.43 m/s after the swimmer runs off, relative to the shore
 
        
             
        
        
        
Answer:
The correct option is (c).
Explanation:
Given that,
The energy of a photon is, 
We need to tell the color of this light. We know that, the energy of a photon is given by :

Where
c is the speed of light

The wavelength of yellow light is approx 580 nm. Hence, we can say that this photon corresponds to yellow light.
 
        
             
        
        
        
Answer:
Height from ground is 8 m where string will break
Explanation:
Let the string makes some angle with the vertical after some instant of time 
So here we have


now by energy conservation we have




For string break down we have


Now height from the ground is given as


