At a place where the acceleration due to gravity is \[10\,m\,{{\sec }^{-2}}\] a force of 5 kg-wt acts on a body of mass 10 kg initially at rest. The velocity of the body after 4 second is [EAMCET 1981]

• A.                              \[5\,m\,{{\sec }^{-1}}\]            
• B.                           \[10\,m\,{{\sec }^{-1}}\]            
• C.                       \[20\,m\,{{\sec }^{-1}}\]          
• D.                           \[50\,m\,{{\sec }^{-1}}\]