M1 Constant Acceleration HELP??

Hi, I'm doing some problems at the moment from the MEI M1 Constant Acceleration, Section 2 Further examples - Level 2 worksheet! Can someone help me with these problems?

1. A particle accelerates from rest with an acceleration of 2ms^-2 to a speed V. It continues at this speed for time T and then decelerates to rest at 1.5ms^-2. The total time for the motion is 1 minute and the total distance travelled in 1km. Find a value for V (use a velocity time graph to help and be systematic)

~ I've drawn a graph but not sure if its a correct representation??


2. A ball is thrown vertically upwards at 25ms^-1. Find the length of time for which the ball is above 3m from the point of projection.

1) Your graph is slightly incorrect. The initial part of the graph, where the velocity is increasing at a constant rate is correct. However, the question states that the particles continues at speed 'V' for time 'T'. You haven't represented that the particle is going at a constant velocity for T seconds on your graph, it should look like a straight line. The last part of the graph is correct!

The graph should end up looking like a trapezium. As the area under a speed time graph represents the distance travelled, you can say that 1000m=The area under the graph. Could you try making an equation that represents the area under the trapezium and then equating that to 1000m?

2) This is a suvat question. We start these by writing down what we know for the values s, u, v, a and t. These questions tend to give you three pieces of information, with the focus on finding a fourth piece using the information you have been given. Here, we know that a=9.8ms^-2, as it is only being acted upon by gravity, we ignore air resistance in M1. We are given the initial speed, u, which is 25ms^-1. And finally, we are given the displacement, s, of the ball that we need to focus on, being 3m. We are given s, u and a and we need to find out t. Therefore, we use the suvat equation containing these four letters and rearrange to find t!

Please ask me if you have any queries regarding my answer, I haven't gone into complete detail on every topic.
If you need additional help, feel free to post here again, but I recommend ExamSolutions, as he does video tutorials on questions like these!

1) Your graph is slightly incorrect. The initial part of the graph, where the velocity is increasing at a constant rate is correct. However, the question states that the particles continues at speed 'V' for time 'T'. You haven't represented that the particle is going at a constant velocity for T seconds on your graph, it should look like a straight line. The last part of the graph is correct!

The graph should end up looking like a trapezium. As the area under a speed time graph represents the distance travelled, you can say that 1000m=The area under the graph. Could you try making an equation that represents the area under the trapezium and then equating that to 1000m?

2) This is a suvat question. We start these by writing down what we know for the values s, u, v, a and t. These questions tend to give you three pieces of information, with the focus on finding a fourth piece using the information you have been given. Here, we know that a=9.8ms^-2, as it is only being acted upon by gravity, we ignore air resistance in M1. We are given the initial speed, u, which is 25ms^-1. And finally, we are given the displacement, s, of the ball that we need to focus on, being 3m. We are given s, u and a and we need to find out t. Therefore, we use the suvat equation containing these four letters and rearrange to find t!

Please ask me if you have any queries regarding my answer, I haven't gone into complete detail on every topic.
If you need additional help, feel free to post here again, but I recommend ExamSolutions, as he does video tutorials on questions like these!