A bridge that was 5 m long has been washed out b he rain sev

A bridge that was 5 m long has been washed out b> (he rain several days ago. How fast must a car be going to successfully jump the stream? Although the road is level on both sides of the bridge, the road on the far side is 2m lower than the road on this side. 25 m/s 36m/s 8m/s 13m/s 5m/s A ball is launched from ground Ievel at 30 m/s at an angle of 35 deg above the horizontal. How far does it go before it is at ground level again? 42m 14 m 128 m 28 m 86 m A cart is given an initial velocity of 5.0 m/s and experiences a constant acceleration of 2.5 m/s^2. What is the magnitude of the cart\'s displacement during the first 6.0 s of its motion? 10 m 66 m 10 m 55 m 75 m A car slows down from a speed of 31 m/s to a speed of 12 m/s over a distance of 380 m. How long does this take, assuming constant acceleration? 21.9 sec 34.2 sec 17.7 sec 14.6 sec 25 sec An object is thrown vertically upward and has a speed of 20 m/s when it reaches three fourth of its maximum height above the launch point. Determine its maximum height. 40.8 10.2 81.6 54.5 20.4 A furlong is a distance of 220 yards. A fortnight is a time period of 2 weeks. A race horse is running at a speed of 4 years per second. What is his speed in furlongs per fortnight? A ball is tossed upward with an initial speed of 27 m/s. How long does it take before the ball is back on the ground? Vector A^- is 3 units is length and points along the positive x-axis, vector B^- is 4 units in length and points along a direction the positive x-axis. What is the direction of the resultant with respect to the positive x-axis in degrees? the top of a cliff 100 m high, Raoul throws a rock upward with velocity 20 m/s. How much later should he drop a so both rocks arrive simultaneously at the bottom of the cliff?

Solution

1.

Time t is calculated as follows:
            s = 1/2gt²

   2 = (1/2)(9.81)(t²)

      t = 0.639 sec

Velocity to jump the stream: v = 5 m / 0.639 sec = 7.82 m/s = 8 m/s (nearly)

option C is correct

2.

The distance is calculated as follows:

R = u0^2sin2@/g = 30*30*sin70/9.8 = 86 m

Option E is correct.

3.

dispalcement is,

   s = ut + 0.5at^2

     = 5*6 + 0.5*2.5*6*6

     = 75 m

Option E is correct.