A plane flying horizontally at 100 ms–1releases an object which reaches the ground in 10s. At what angle with horizontal it hits the ground?



1. 55°

2. 45°

3. 60°

4. 75°


Asked by devanshmalhotra2609 | 9th Jan, 2016, 01:43: AM

Expert Answer:

begin mathsize 12px style Let space straight v subscript straight x space and space straight v subscript straight y space be space the space component space of space velocity space of space the space object. straight u subscript straight y equals 0 comma space straight a subscript straight y equals 9.8 space straight m divided by straight s squared comma space straight v subscript straight y equals ? comma space straight t space equals space 10 space straight s as comma space straight v subscript straight y equals straight u subscript straight y plus straight a subscript straight y straight t therefore straight v subscript straight y equals 0 plus 9.8 cross times 10 equals 98 space straight m divided by straight a Now comma straight u subscript straight x equals 100 space straight m divided by straight s comma space straight a subscript straight x equals 0 comma space straight v subscript straight x equals ? comma space straight t equals 10 space straight s as comma space straight v subscript straight x equals straight u subscript straight x plus straight a subscript straight x straight t therefore straight v subscript straight x equals 100 plus 0 cross times 10 equals 100 space straight m divided by straight s Let space straight theta space be space an space angle space with space the space horizontal space direction. tan space straight theta equals straight v subscript straight y over straight v subscript straight x equals 98 over 100 equals 0.98 straight theta equals tan to the power of negative 1 end exponent 0.98 equals 44 degree 42 apostrophe almost equal to 45 degree end style

Answered by Priyanka Kumbhar | 11th Jan, 2016, 10:18: AM